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Bihar Board 12th Business Studies Model Papers

Bihar Board 12th Business Studies Model Question Paper 1 in English Medium

Time : 3 Hour 15 Min
Full Marks : 100

Instructions

1. Candidates are required to give their answers in their own words as far as practicable.
2. Figures in the right hand margin indicate full marks.
3. 15 minutes of extra time has been allotted for the candidate to read the questions carefull.
4. This question paper has two sections : Section -A and Section-B.
5. In Section-A, there are 50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with black/blue ball pen against the correct option on OMR Sheet provided to you. Do not use Whitener/ Liquid/Blade/Nail on OMR Sheet, otherwise the result will be treated as invalid.
6. In Section-B, there are 25 Short answer type questions, out of which any 15 questions are to be answered. Each question carries 2 marks. Apart from this, there are 08 Long answer type questions, out-of which any 04 of them are to be answered. Each question carries 5 marks.
7. Use of any electronic device is prohibited.

Objective Type Questions

Question No. 1 to 50 have four options provided, out of which only one is correct. You have to mark, your selected option, on the OMR-Sheet. Each question carries 1 (one) mark. [50 x 1 = 50]

Question 1.
The essence of management is :-
(a) Co-ordination
(b) Organisation
(c) Staffing
(d) All of these
Answer:
(a) Co-ordination

Question 2.
New Economic Ploicy is :-
(a) Liberalisation
(b) Privatisation
(c) Globalisation
(d) All of these
Answer:
(d) All of these

Question 3.
The organization steps are :-
(a) 2
(b) 4
(c) 6
(d) 8
Answer:
(b) 4

Question 4.
Training is a process
(a) Current
(b) Regular
(c) Continuous
(d) All of these
Answer:
(d) All of these

Question 5.
Controlling is necessary in :-
(a) Small enterprise
(b) Medium Enterprise
(c) Large Enterprise
(d) All of the above
Answer:
(d) All of the above

Question 6.
Characteristics of a sound financial planning are: –
(a) Simplicity
(b) Liquidity
(c) Economy
(d) All of these
Answer:
(d) All of these

Question 7.
First Function of financial management is :-
(a) Procurement of fund
(b) Financial forecasting
(c) Financial Control
(d) None of these
Answer:
(a) Procurement of fund

Question 8.
Co-ordination is :-
(a) Voluntary
(b) Necessary
(c) Unecessary
(d) Wastage of time
Answer:
(b) Necessary

Question 9.
By Scientific Management profits are :-
(a) Increased
(b) Decreased
(c) Not affected
(d) Revival
Answer:
(a) Increased

Question 10.
Economic Environment ofbusiness is influenced by :
(a) Economic policy
(b) Economic system
(c) Economic development
(d) All of these
Answer:
(d) All of these

Question 11.
Staffing is the responsibility of.
(a) Lower management
(b) Middle management
(c) Top management
(d) All of these
Answer:
(d) All of these

Question 12.
According to George R. Terry, The type of planning are :-
(a) 08
(b) 06
(c) 04
(d) 02
Answer:
(d) 02

Question 13.
An organization is not helpful lor :-
(a) Co-ordination
(b) Contributes to morale
(c) Increase in corruption
(d) Incentive to growth
Answer:
(c) Increase in corruption

Question 14.
Employees Training is :-
(a) Necessary
(b) Unnecessary
(c) Compulsory
(d) Wastage of Money
Answer:
(c) Compulsory

Question 15.
Direction is related to employees :-
(a) Top level
(b) Middle level
(c) Lower level
(d) All level of above
Answer:
(d) All level of above

Question 16.
Organising process involves :-
(a) Grouping of indentical work
(b) Division of a work
(c) Assigning work to appropriate persons
(d) All of these
Answer:
(d) All of these

Question 17.
Fixed-capital is required for :-
(a) Payment of routine expenses
(b) Purchase of land
(c) Depositing in bank
(d) Payment to creditors
Answer:
(b) Purchase of land

Question 18.
SEBI is controller of :-
(a) Production
(b) Insider trading
(c) Capital marketing
(d) Government
Answer:
(c) Capital marketing

Question 19.
Entrepreneurship is an effort to create :-
(a) Risk
(b) Profit
(c) Jobs
(d) Business
Answer:
(c) Jobs

Question 20.
Working non-government organization in India is :-
(a) VOICE
(b) Common Cause
(c) A and B both
(d) None of these
Answer:
(c) A and B both

Question 21.
The Advantage of marketing is to :-
(a) Consumers
(b) Businessmen
(c) Manufacturers
(d) All of these
Answer:
(d) All of these

Question 22.
Onwner’s Fund does not indued :-
(a) Share Capital
(b) Bank Loan
(c) Reserve Fund
(d) Share Premium
Answer:
(b) Bank Loan

Question 23.
Labelling is :-
(a) Compulsory
(b) Necessary
(c) Voluntary
(d) Wastage of Money
Answer:
(a) Compulsory

Question 24.
Consumer rights under Consumer Protection Act. are :-
(a) 08
(b) 07
(c) 06
(d) 10
Answer:
(a) 08

Question 25.
Social and economic development of a nation is the result of :-
(a) Entrepreneur
(b) Planning
(c) Operation
(d) Government
Answer:
(a) Entrepreneur

Question 26.
Advertising is done for :-
(a) Development of business
(b) Financial management
(c) Sales promotion
(d) Public relations
Answer:
(c) Sales promotion

Question 27.
Maximum period of treasury bill is :-
(a) One year
(b) Two years
(c) Five years
(d) Ten years
Answer:
(a) One year

Question 28.
Supervision is :-
(a) Necessary
(b) Unnecessary
(c) Wastage of time
(d) None of these
Answer:
(a) Necessary

Question 29.
Controlling is the function of
(a) Supervisor
(b) Sales man
(c) Mariager
(d) Employee
Answer:
(a) Supervisor

Question 30.
Steps Involved in selection process :-
(a) 07
(b) 09
(c) 06
(d) 10
Answer:
(a) 07

Question 31.
Depends on the sweet will of employees :-
(a) Divisional organisation
(b) Formal organisation
(c) Functional organisation
(d) Informal organization
Answer:
(d) Informal organization

Question 32.
Planning is not :-
(a) Mental exercise
(b) Forward looking
(c) Wastage of time
(d) Choosing process
Answer:
(d) Choosing process

Question 33.
The need in development of a country is :-
(a) Physical resources
(b) Economic resources
(c) Efficient management
(d) All of these
Answer:
(d) All of these

Question 34
14 principles of management is propounded by :
(a) Henary Feyol
(b) F. W. Taylor
(c) Peter Drucker
(d) A. H. Maslo
Answer:
(a) Henary Feyol

Question 35.
Liberalisation policy in India has been :-
(a) Successful
(b) Unsuccessful
(c) Normal
(d) None of these
Answer:
(a) Successful

Question 36.
Planning is helpful to :-
(a) Achieving objectives
(b) In co-ordination
(c) Effective controlling
(d) All of these
Answer:
(d) All of these

Question 37.
Wages given to workers in Traditional Management are :-
(a) Low
(b) High
(c) Normal
(d) Maximum
Answer:
(d) Maximum

Question 38.
Which of the following is not features of organization : –
(a) Group of Individuals
(b) Group of Machine
(c) A Structure
(d) A process
Answer:
(b) Group of Machine

Question 39.
Objective of employee’s development is :-
(a) Increase in knowledge
(b) Better performance
(c) opportunity of promotions
(d) All of these
Answer:
(d) All of these

Question 40.
Which of the following is not external sources of recruitment: –
(a) Transfer of employees
(b) Direct recruitment
(c) Campus recuitment
(d) Contractual recruitment
Answer:
(a) Transfer of employees

Question 41.
Type of communication are :-
(a) Written
(b) verbal
(c) Formal
(d) All of these
Answer:
(c) Formal

Question 42.
The leader possess :-
(a) Intelligence
(b) Foresightness
(c) Self-confidence
(d) Ail of these
Answer:
(d) Ail of these

Question 43.
In- effective communication language should not be :-
(a) Express
(b) Impressive
(c) Ambiguous
(d) Courtesy
Answer:
(d) Courtesy

Question 44.
Control is by employees.
(a) Opposed
(b) Supported
(c) Liked
(d) None of these
Answer:
(a) Opposed

Question 45.
The sources of working capital are :-
(a) Debtors
(b) Bank overdraft
(c) Cash sales
(d) All of these
Answer:
(a) Debtors

Question 46.
Capital market deals in
(a) Short term funds
(b) Medium term funds
(c) Long term funds
(d) None of these
Answer:
(c) Long term funds

Question 47.
Financial manager takes decision as to
(a) Finance
(b) Investment
(c) Dividend
(d) All of above
Answer:
(d) All of above

Question 48.
Consumer Protection Act was passed
(a) In 1886
(b) In 1986
(c) In 1996
(d) In 1997
Answer:
(b) In 1986

Question 49.
In India, entrepreneurial development programmer has been
(a) Successful
(b) Unsuccessful
(c) Need of improvement
(d) None of these
Answer:
(c) Need of improvement

Question 50.
Importance of Marketing concept is for
(a) Society
(b) Consumers
(c) Producers
(d) All of above
Answer:
(d) All of above

Non-Objective Type Questions

Short Answer Type Questions

Question no. 1 to 25 are Short answer type questions. Answer any 15 out of them. Each question carries 2 marks. (15 x 3 = 30)

Question 1.
Write the name of the level of manage-ment.
Answer:
Following are the level of management :

1. Top Level Management
2. Middle Level Management
3. Lower Level Management.

Question 2.
Write any three points of the nautre of principles of management.
Answer:
Management of Principles : These are the statement of fundamental truth based on creation and systematic analysis which provides guidlines for managerial decision making and action.
Nature and charecteristics of management Principles are the same which are following :

1. Flexibility
2. Univarsal application
3. lack of humanimity
4. Beharourial.

Question 3.
Write the name of any four factors of business environment.
Answer:
Principles of Management :

1. Division of work : This means assigning the work to a person for which he is best suited. This principle is equally applicable to all hands of work managerial as well as technical.
2. Unity of command : This means that sub-ordinates should be receive orders from one senior only. A sub-ordinate receiving orders from two or more bosses can satisfy none.
3. Dicipline : Disciplines mean the observance of rules and regulations this principle emphasises the obedience on the part of the sub-ordinates.

Question 4.
Write name of any four merits of scientific management.
Answer:
Following are the merit of scientific management :

1. Reduction in the cost of production.
2. Better quality products.
3. Benefits of division of labour.
4. Avoidance of disputes between labour and management.

Question 5.
State any two types of planning on the basis of level of management.
Answer:
Types of planning on the basis of level of management are discussed below :

1. Operational plan
2. Tactical plan.
3. Strategical plan

Question 6.
State any four points of importance of organization.
Answer:
Importance of organisation are discussed below :

1. Makes the management simple and efficient.
2. Encourage specilization.
3. Improves constructive tainking.
4. Increase productivity.

Question 7.
Write the name of any five advantage of organization in business.
Answer:
Advantages of organisation are following :

1. Specilization
2. Role clarity
3. Clarifies authority and responsibility.
4. Avoiding duplication of work.
5. Co-ordination.

Question 8.
State any three qualities of a good leader.
Answer:
Qualities of a good leader are mention below:

1. Physical features
2. Knowledge
3. Integrity
4. Communication skills.
5. Motivation skills.
6. Initiative
7. Self confidence
8. Decisiveness
9. Social skills.

Question 9.
State name of any two methods of ‘on-the- job training.
Answer:
Following are the two methods of “on job training”.

1. Internship training method.
2. Case study method.

Question 10.
State any three barriers of. communication.
Answer:
Effective communication is essential for effective and efficient management of an organisation.
There are a number of barriers to effective communications,
such as :

1. Semantic barriers,
2. Psychological or Emotional barriers,
3. Organisational barriers
4. Personal barriers.

Question 11.
State any two headings of the importance of supervision.
Answer:
Following are the two importance of supervision :

1. Optimum utilization of Resoures : Supervision develops work skills which help in optimum utilization of resources.
2. Controlling performance : Supervision insures performance of work as per the targets.
   Supervisior assumes responsibility for the accomplish ment of task. Undertaken and motivates his fellow workers.

Question 12.
Write any four headings of the importance of control in management.
Answer:
Following are the four heading of importance of control in management :

1. Control is basis of planning.
2. Facilitates decision making.
3. Helps in improving efficiency.
4. Appraisal of performance.

Question 13.
Write name of any three methods/ techniques of control.
Answer:
Following are the methods/Techniques of control :

1. Budgetary control.
2. Break-even analysis.
3. Statistical Data.
4. Special reports and Analysis.
5. Operational Audit or Internal Audit.
6. Personal Observation.
7. Policies, Procedures and Instructions.
8. Ratio Analysis.
9. Other Techniques.

Question 14.
Write the name of any three financial decisions taken by management.
Answer:
The three main financial decision which are generally taken by a finance manager are as under.,

1. Investment Decision.
2. Financial Decision.
3. Dividend decision.

Question 15.
Write the name of any four factors which include in capital structure.
Answer:
Following are the four factors which include in capital structure :

1. Position of cash flow.
2. Cost of capital.
3. Return on investment.
4. Risk consideration.

Question 16.
Name the two factors affecting capital structure.
Answer:
Following are the two factors affecting capital structure.

1. Cost of capital.
2. Risk consideration.

Question 17.
State any four functions of financial market.
Answer:
Following are the four important functions of financial market :

1. Mobilisation of savings and channelising them into most productive uses.
2. Informational role for price recovery.
3.  Providing liquidity to financial assets.
4. Reducing the cost of transactions.

Question 18.
Write the two headings of the function of SEBI.
Answer:
Following are the two heading of SEBI functions :

1. Protective functinsz.
2. Development functions.

Question 19.
Name any four media of advertisement.
Answer:
Following are the four medium of advertising:

1. Newspapers
2. Magazines
3. Television
4. Radio.

Question 20.
State any two characteristics of a good brand.
Answer:
Following are the two features of good brand :

1. It should be distinctive.
2. It should be appropreate.

Question 21.
State any two objectives of consumer protection programme.
Answer:
The main two objectives of consumer protection act are as below :

1. To ensure fair, competitive and responsible markets that work well for consumers and promote ethical business practice.
2. To promote and protect the economics interests of consumers.

Question 22.
State any two characteristics of entrepreneurship.
Answer:

1. Innovation : Any innovative work is entrepreneurship. New resources, new products, new technology, new utilities, new managerial skills etc., come in the perview of entrepreneurship. Thus, the basic feature of entrepreneurship is innovation.
2. A high achievement function : Achievement orientation is the most important factor for explaining economic behaviour. ‘Doing things in a new and a better way’ and ‘decision-making under uncertainty’, can be regarded as two important features of entrepreneurship.

Question 23.
Name the needs which should be satisfied first.
Answer:
Following are five basic needs which should be satisfied first.

1. Physological needs.
2. Safety needs.
3. Love and belongingness needs.
4. Esteem needs.
5. Self actualization needs.

Question 24.
Write any three merits of advertising.
Answer:
Following are the merits of Advertising :

1. Introduces new product in the market.
2. Expansion of the market.
3. Increased sales.
4. Fight competition.
5. Enhance goodwill.
6. Elimination of middlemen.
7. Better quality products.
8. Educate the consumers.

Question 25.
Name any three sourcess of raising fixed capital.
Answer:
Following are the three sources of raising fixed capital :

1. Issue of equity and preference shares.
2. Issue of Debentures.
3. Issue of Right shares.
4. Retained Earning.

Long Answer Type Questions

Question no. 26 to 33 are Long answer type questions. Answer any 4 of them. Each question carries 5 marks. (4 x 5 = 20)

Question 26.
What is divisional organization ? State its main characteristics.
Answer:
Divisional Organisation/Departmentation: A department is a work group or unit which is created for performing certain functions of .similar nature. The process of division of the enterprise into different parts is broadly called departmentation.

The various parts or divisions are called as departments. It leads to grouping of both functions and personnel who are assigned to carry out allocated functions. It helps in creating a sound organisation structure. There can be many methods of departmentation. Every enterprise choose the appropriate basis or method depending upon its objectives, size, etc.

Merits :

1. This arrangement makes effective control possible
2. This arrangement is based on the principle of specialisation
3. It estrablishes co-ordination on the departmental level.

Demerits :

1. The weakness of one department affects the other departments
2. All the departments function according to their sweet will making inter-departmental co-ordination difficult
3. This system is q hurdle in the way of the complete development of the employees.

Question 27.
Explain the importance of decentralization.
Answer:
Decentralisation refers to the systematic effort to delegate to the lowest level all authority except which can be exercised at the central point.

The following factors highlight its importance :

1. Greatern Motivation : Decentralisation improves the morale and motivation of Subordinates which is reflected in better work performance.
2. Develops initiative among subordinates : Decentralisation helps to promote self-reliance and confidence amongst the subordinates. This is because when lower managerial levels are given freedom to take their own decisions, they learn to depend on their own judgement. It helps to promote initiative and creativity among them.
3. Develops managerial talent for the future : As a result of decentralisation, employees get more opportunities to develop new skills. It makes them better future managers.
4. Quick decision making : Decentralisation in an organisation, provides more freedom to lower level managers to take their own decisions. There is no need to get approval from higher level. It helps in quick and better decision making.
5. Facilitates growth and expansion : Decentralisation facilitates organisational growth through expansion and diversification.

Question 28.
Explain in brief the various methods of training.
Answer:
There are various methods of training. These are broadly categories into two groups :

• On the job.
• off-the job methods.

On the job methods :

1. Apprenticeship programmes: Apprenticeship programmes put the trainee under the guidance of master worker. These are designed to acquire a higher level of skill.
2. Coaching : In this method, the superior guides and instructs the trainee as a coach. The coach or counseler sets mutually agreed upon goals.
3. Internship training : It is a joint programme of training in which educational instigutions and business firms cooperate.
4. Job rotation : This kind of training involves shifiting the trainee from one department to another of from or one job to another.

Off the job methods:

1. Class room lectures/conferences: The lecture or conference approach is well adapted to conveying specific information rules, procedures or methods.
2. Films : They can provide information and explicitly demonstrate skills that are not easily represened by the other techniques.
3. Case study : Taken from actual experiences of organisations, cases represent attempts to describe,
   as accruetly as possible real problems that managers have faced.
4. Computer modelling: It simulates the work environment by programming a computer to imitate some of the realities of the job and allows learning to take place without the risk or high costs.
5. Vestibule training : Employees learn their jobs on the equipment they will be using, but the training is conducted away from the actual work floor.
6. Programmed instruction : The method incorporates a prearranged and proposed acuisition of some specific skills or general knowledge.

Question 29.
Discuss the importance of directing.
Answer:
Following are the importance of Directing :

1. Managerial function : Directing is a managerial function. It is through directing, the managers guides, inspires and leads the employees to perform the task assigned.
2. Continuing function : Directing is a continuous function. The managers continuously guide, inspire and lead the employees to get the work done.
3. Integrating process : Directing is an integrating process. It integrates the efforts of the employees to achieve the organisational objectives. It provides direction to their efforts. In the absence of direction, their efforts may not focus or concentrate on the objectives of the organisation and may remain inactive.
4. Pervasive function : Directing is a responsibility of all managers. It is performed at all levels of the organisation. Directing flow from top to lower levels of management.
5. Creative function : Driecting is a creative function. It converts paper plans into reality by initiating, guiding, leading and supervising.

Question 30.
Explain any four needs that motivate an employee to work.
Answer:
Froms of Non-financial Incentives: In order to motivate the employees management may use the following forms of non-financial incentives :

(i) Praise of appreciation of work done : Recognition of satisfactory performance acts as non- financial incentive since it satisfies one’s ego needs. However, this incentive should be used with great care because praising an incompetent employee creates resentment among competent employees.

(ii) Workers’ participation in management : Participation in management provides strong motivation to the employees. Gives them psychological satisfaction if there voice is header participants in management provides for two ways communication and so imbibes a sense of importance.

(iii) Suggestion system : Suggestion system is an incentive with satisfies many needs of the employees. Many organisations which use the suggestion system make use of cash awards for useful suggestion. They sometimes publish the workers name with the photograph in the company magazine. This motivates the employees to be in search for something which may be of greater use to the organisation.

(iv) Competition : If there is healthy competition among individual employees, group of employees, it leads them to achieve their persoanl or group goals. Hence, competition acts as none financial incentives.

(v) Opportunity for growth : Opportunity for growth is another kind of intensive. If the employees are provide opportunity for their advertisement and growth to develop their personality, they feel very much satisfied and more communicate to organisation goals.

Question 31.
Explain the functions of financial manager.
Answer:
Finances are the cornerstone of every business. The prime goal of my organization would be to garner huge profits and this is only possibe withh proper management of the finance. Therefore, effectual finance Management is imperative for every organization as it leads to enhanced profits are reduction in the operational cost.

A finance manger plays an impoertant role in the mangement of a business organbization as he manges all the activites related to finance. There are many functions that a financial manager is expected to perform .
These include.

1. Estimating the amount of capital required for the proper functioning of the business : The most basic function of a finance manager is the estimation of the capital because funds are required for both long term and short term. The firm requires capital so that it can its liability with no delay, benefit from early business opportunites, pay for resources, op-erational cost etc.

2. Devising a capital structure : For the determining the capital structure, the finance manager must ensure that the earning rate is higher than the rate of interest on the borrowed amount.

3. Sources to raise funds : For proper financial management, it is imperative to find can raise funds. The organisatiion can raise funds through different sources including equity and preference shares, debentures, banks, financial institutions other souces.

4. Acquisition of funds : While acquiring funds, the financial manager needs to follow some basic step such as legal formalities and documentation’ required.

Question 32.
What is working capital ? How is it calculated ?
Answer:
Meaning of Working Capital : Working capital refers to that capital which is utilized for meeting current liabilities by cash payments in the ordinary course of business. In other words, the working capital is invested in raw materials, in stock of partly finished goods in meeting day-to-day or current exenditure on salaries, wages, rent, rates, taxes, insurance, advertisement etc. in cash.
Determinants of Working Capital
(1) Size of Business : Larger of the business enterprise, greater would be the need for working capital. The size of a business may be measured in terms of scale of its business operations.

(2) Production Cycle : Production cycle means the time-span between the purchase of raw materials and its conversion into finished goods. The longer the production cycle, the larger will be the need for working capital.

(3) Production Policy : The need for working capital is also determined by production policy. The demand for certain products (such as woolen garments) is seasonal. Two type of production policies may be adopted for such products.

(4) Availability of Raw Material : If the raw material required by the firm is available easily on a continuous basis, there will be no need to keep a large inventory of such materials and hence the requirement of working capital will be less. On the other hand, if the supply of raw material is irregular, the firm will be compelled to keep an excessive inventory of such materials which will result in high level of working capital.

(5) Availability of Credit from Banks :If a firm can get easy bank credit facility in case of need, it will operate with less working capital

Question 33.
Explain any five functions of marketing.
Answer:
Function of Marketing:
(i) Gatrhering and analysing market information : An important function of a marketer is gather and analyse market information. It is necessary to identify the needs the customers and to take various decisions for the successful marketing of the products and services.

(ii) Marketing planning : Marketing manager has to develop appropriate marketing plans to achieve the marketing objectives of the firm.

(iii) Customers support services : Another very important function of marketing management relates to developing customers support serves such as procuring credit service after sales services, handling customer complaints, maintenance services, technical services and consumer information. All these services aim at providing maximum satisfaction to the customers.

(iv) Physical distributions : A very important function of marketing is to arrange for distribution o f goods and services. Physical distribution includes decisions regarding choice of channels of distribution, maintaining inventory, storange, warehousing etc.

(v) Utilising funds : It is the task of the finance manager to ensune that the funds are inuested wisely so as to garner maximum roll.

(vi) Disposing of Profits : Effectcial finance management involves Inalysing the funds that can be invested for proper working of the organization and distributing the rest amoung the shareholders.

(vii) A financial manager needs to manage the cash in such a way that there its neither shortage nor surplus and decily expenses can be met without any hassles.

(viii) Finance Management involves avaluation and control of the financial perform once of an organization

Bihar Board 12th Economics Model Papers

Bihar Board 12th Economics Model Question Paper 5 in English Medium

Time : 3 Hour. 15 Min
Full Marks : 100

Instructions

1. Candidates are required to give their answers in their own words as far as practicable.
2. Figures in the right hand margin indicate full marks.
3. 15 minutes of extra time has been allotted for the candidate to read the questions carefully.
4. This question paper has two sections : Section-A and Section-B.
5. In Section-A, there are 50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with black/blue ball pen against the correct option on OMR Sheet provided to you Do. not use Whitener/Liquid/Blade/Nail on OMR Sheet, otherwise the result will be treated as invalid.
6. In Section-B, there are Non-objective type questions. There are 25 Short answer type questions, out of which any 15 questions are to be answered. Each question carries 2 marks. Apart froms this, there are 08 Long answer type questions, out-of which any 04 of them are to be answered. Each questions carries 5 marks.
7. Use of any electronic device is prohibited.

Objective Type Questions

Question No. -1 to 50 have four options provided, out of which only one is correct. You have to mark, your selected option, on the OMR-Sheet. Each questiion carries 1 (one) mark. [50 x 1 = 50]

Question 1.
Which is a central problem of an economy ?
(a) Allocation of Resources
(b) Optimum utilization of Resources
(c) Economic development
(d) All of these
Answer:
(d) All of these

Question 2.
Which of the following is a source of production ?
(a) Land
(b) Labour
(c) Capital
(d) All of these
Answer:
(d) All of these

Question 3.
According to whom, Economics is a science of human welfare ?
(a) A. Marshall
(b) Paul Samuelson
(c) J.S.Mill
(d) Adam Smith.
Answer:
(a) A. Marshall

Question 4.
Which of the following is not a factor of production ?
(a) Land
(b) Labour
(c) Money
(d) Capital
Answer:
(c) Money

Question 5.
The word ‘micro’ was first used by __________
(a) Marshall
(b) Boulding
(c) keynes
(d) Ragnar Frisch
Answer:
(d) Ragnar Frisch

Question 6.
Consumer’s behaviour is studied in __________
(a) Micro-economics
(b) Income theory
(c) Macro-economics
(d) None of these
Answer:
(a) Micro-economics

Question 7.
Elasticity of demand for necessary goods is __________
(a) zero
(b) unlimited
(c) greater than unity
(d) less than unity
Answer:
(a) zero

Question 8.
Which of the following factors affects elasticity of demand ?
(a) Nature of goods
(b) Price level
(c) Income level
(d) All of these
Answer:
(d) All of these

Question 9.
Law of demand is a __________
(a) Qualitative statement
(b) Quantitative statement
(c) Both (a) and (b)
(d) None of these
Answer:
(c) Both (a) and (b)

Question 10.
In production function, production is a function of __________
(a) price
(b) factors of production
(c) total expenditure
(d) None of these
Answer:
(b) factors of production

Question 11.
At which time all the factors of production may be changed ?
(a) Short run
(b) Long run
(c) Very long run
(d) All of these
Answer:
(a) Short run

Question 12.
Average variable costs can be defined as __________
(a) TVC x Q
(b) TVC + Q
(c) TVC – Q
(d) TVC -r Q
Answer:
(d) TVC -r Q

Question 13.
For a firm’s equlibrium __________
(a) MR = MC
(b) MR > MC
(c) MR < MC
(d) MR = MC = 0
Answer:
(a) MR = MC

Question 14.
Supply is associated with __________
(a) a time period
(b) price
(c) both (a) and (b)
(d) none of these
Answer:
(c) both (a) and (b)

Question 15.
Determining factor of supply of goods is __________
(a) Price of goods
(b) Price of related goods
(c) Price of factors of production
(d) All of these
Answer:
(d) All of these

Question 16.
Which is a characteristic of the market ?
(a) One area
(b) Presence of Buyers and” Sellers
(c) Single price of the commodity
(d) All of these
Answer:
(d) All of these

Question 17.
Which one is a feature of monoplistic competition ?
(a) Differentiated product
(b) Selling cost
(c) Imperfect knowledge of the market
(d) All of these
Answer:
(d) All of these

Question 18.
Which is a reason of change in demand ?
(a) Change in Consumer’s Income
(b) Change in price of related goods
(c) Population increase
(d) All of these
Answer:
(d) All of these

Question 19.
Net National Income at factor cost is called __________
(a) National Income
(b) Gross Investment
(c) Income
(d) None of these
Answer:
(a) National Income

Question 20.
Depreciation expenses are included in __________
(a) GNPMP
(b) NNPMP
(c) NNPpc
(d) none of these
Answer:
(a) GNPMP

Question 21.
Which one is included in three sector model ?
(a) Family
(b) Goverment
(c) Firm
(d) None of these
Answer:
(b) Goverment

Question 22.
Which service is included in Tertiary sector ?
(a) Mining
(b) Construction
(c) Communication
(d) Animal Husbandry.
Answer:
(d) Animal Husbandry.

Question 23.
Which method is adopted in measuring National Income ?
(a) Production method
(b) Income method
(c) Expenditure method
(d) All of these
Answer:
(d) All of these

Question 24.
“Money is what money does”- Who said it ?
(a) Hawtrey
(b) Keynes
(c) Hartley Withers
(d) Prof. Tinbergen
Answer:
(c) Hartley Withers

Question 25.
Which is the primary function of commercial banks ?
(a) Accepting deposits
(b) Advancing loans
(c) Credit creation
(d) All of these
Answer:
(d) All of these

Question 26.
The full form of ATM is __________
(a) Any Time Money
(b) All Time Money
(c) Automated Teller Machine
(d) both (a) and (b)
Answer:
(c) Automated Teller Machine

Question 27.
Reserve Bank of India was established in __________
(a) 1947
(b) 1935
(c) 1937
(d) 1945
Answer:
(b) 1935

Question 28.
Micros which means ‘small’ belongs to which language ?
(a) Arabic
(b) Greek
(c) German
(d) English
Answer:
(b) Greek

Question 29.
How many types of elasticity of demand is there ?
(a) Three
(b) Five
(c) Six
(d) Seven
Answer:
(b) Five

Question 30.
Which money is issued by the central bank ?
(a) Currency
(b) Credit money
(c) Coins
(d) All of these
Answer:
(b) Credit money

Question 31.
RBI announced the guidelines to issue itences to new banks of Private Sector on __________
(a) January 22, 1993
(b) March 15,1995
(c) April 1,1999
(d) None of these
Answer:
(a) January 22, 1993

Question 32.
Banking Sector Reforms in India began in __________
(a) 1969
(b) 1981
(c) 1991
(d) 2001
Answer:
(c) 1991

Question 33.
“Supply creates its own demand” Who gave this law ?
(a) J. B. Say
(b) J.S.Mill
(c) Keynes
(d) Ricardo.
Answer:
(c) Keynes

Question 34.
On Which factor does Keyneaian theory of employment depend ?
(a) Effective demand
(b) Supply
(c) Production efficiency
(d) None of these
Answer:
(a) Effective demand

Question 35.
Who is the writer of the book. ‘Traited Economic Politique’ ?
(a) Pigou
(b) J. B. Say
(c) Keynes
(d) Ricardo
Answer:
(b) J. B. Say

Question 36.
If MPC = 0.5 then mulutiplier (k) will be __________
(a) i-
(b) 0
(C) f
(d) 2
Answer:
(d) 2

Question 37.
On which concept does classical viewpoint depend ?
(a) Say’s law of market
(b) Perfect Flexibility of wage Rate
(c) Perfect Flexibility of Interest Rate
(d) All of these
Answer:
(b) Perfect Flexibility of wage Rate

Question 38.
Which is included in indirect tax ?
(a) Income tax
(b) Wealth tax
(c) Excise duty
(d) Gift tax
Answer:
(c) Excise duty

Question 39.
Which one is the item of Current Account ?
(a) Import of visible items
(b) Expenses of tourists
(c) Export of visible items
(d) All of these
Answer:
(d) All of these

Question 40.
Balance of trade means __________
(a) capital transaction
(b) import & export of goods
(c) total debit and credit
(d) all of these
Answer:
(d) all of these

Question 41.
What is price flexibility of a necessities of demanded things ?
(a) Zero
(b) Infinite
(c) More then a unit
(d) less than unit
Answer:
(a) Zero

Question 42.
‘Profit is the award of bearance risk’ who said this ?
(a) Halley
(b) J. B. Clark
(c) Knight
(d) None of these
Answer:
(c) Knight

Question 43.
The market situation in which there is only are consumer is called __________
(a) Monopoly
(b) Monopsani
(c) Duopoly
(d) None of these
Answer:
(c) Duopoly

Question 44.
On which matter it is decide of general value, __________
(a) market day
(b) short-term market
(c) long term market
(d) none of these
Answer:
(b) short-term market

Question 45.
Following is not a source of origin __________
(a) Land
(b) Labour
(c) Money
(d) Capital
Answer:
(c) Money

Question 46.
Who the Central Bank of India ?
(a) SBI
(b) Central Bank of India
(c) Reserve Bank of india
(d) None of these
Answer:
(c) Reserve Bank of india

Question 47.
When was establish Reserve Bank of India ?
(a) In 1932
(b) In 1935
(c) In 1945
(d) In 1956
Answer:
(b) In 1935

Question 48.
In which year the nationalisation of the commercial bank:
(a) 1960
(b) 1968
(c) 1969
(d) 1980
Answer:
(c) 1969

Question 49.
Central Bank can control by which __________
(a) Bank Rate
(b) Open market
(c) CRR
(d) All these
Answer:
(d) All these

Question 50.
When was establish State Bank of India ?
(a) 1950
(b) 1955
(c) 1960
(d) 1965
Answer:
(b) 1955

Non-Objective Type Questions

Short Answer Type Questions

Question no. 1 to 25 are Short answer type questions. Answer any 15 out of them. Each question carries 2 marks. (15 x 3 = 30)

Question 1.
State any four difficulties of Barter System.
Answer:
The four difficulties of Barter system are as follows:

1. Lack of Double Coincidence : The barter system requires a double coincidence of wants on the part of those who want to exchange goods or services. lt is necessary for a person who wishes to trade his goods or service to find some other person who is not willing to buy his goods or service,but also possesses that goods which the former wants.
2. Difficulties in store value : A major difficulty in barter system appears because store of purchasing power for future can not be made due to perishable nature of most of the goods.
3. Lack of common acceptability unit of value : Due to lack of common acceptable unit of value ,it becomes difficult to determine.The value of commodity to be exchanged.
4. Lack of divisibility in commodities: Another difficulty of barter system relates to the fact that all commodities can not be divided or sub-divided.

Question 2.
What is law of supply ? Explain it with illustration.
Answer:
The law of supply states, that other things remaining constant, the higher the price, the greater the quantity supplied or the lower the price, the smaller the quantity supplied.Law of supply states the positive relationship between price of the commodity and its supply.Producer always wants to sell his commodity at a higher price and less at a lower price .Thus,price of commodity and its supply are positively related.In functional form.S = f (P) Where S refers to supply of the commodity and P for price.Thus,supply function of a commodity represents a direct relationship between supply of commodity and its price.

The law of supply can also be explained with ‘Supply schedule’ and ‘Supply Curve.

Above table shows individual supply schedule, that explains supply of commodity increases with increase in price.

Question 3.
Discuss the main features of government budget.
Answer:
The main features of Government budget are as follows:

1. Encouragement to economic development: The basic objective of the budget is to accelerate the pace of economic development in the country.For accelerating the pace of economic development:
   • government may grant tax rebates to productive activities
   • government may develop infrastructure like roads .bridges etc.
   • government may establish public enterprises.
2. Balanced Regional Development : Through budget .government may promote the development in backward areas for ensuring balanced regional development in the economy. Engorgement may grant tax rebates to these areas,may establish public enterprises in these areas and may allocate more funds for infrastructural development in these backward areas.
3.  Re- distribution of income and property : Budget plays a vital role in reducing the economic disparities in the economy.Many steps can be taken in the budget for reducing the economic disparities in the economy.
4. Economic Stability: Economy faces the cycles of boom and depression and the budget aims to put a control on these cycles.
5. Creation of employment : Employment creation is one of the important objectives of government budget.Govemment may promote labour – intensive techniques in public works programmes and may also initiate programmes in the economy.

Question 4.
Distinguish between primary sector and secondary sector.
Answer:
Difference between Primary sector and secondary sector are as follows :
Primary sector :

1. It is that sector which exploits natural resources and produce goods and services.
2. It is known as agriculture and allied sector.
3. It includes all agricultural and allied activities such as forestry,mining,quarrying,fishing,animal husbandry etc.
4. Unorganised and traditional techniques.
5. No possibility of division of labour.

Secondry sector :

1. It is that sector which transforms one goods into another for creating more utility from it.
2. Famously known as manufacturing sector.
3. It includes manufacturing units small scale units, large firms ,big corporate, multinational corporation.
4. Organised techniques.
5. Complex division of labour can be used for production.

Question 5.
What is National Income ?
Answer:
National income is the sum of factor incomes earned by normal residents of a country during the period of one year.

NY = National income
Z = Sum or total (Z is called sigma)
FY = Factor income
n = all normal residents of a country.
Rent, interest, profit and wages are the factor incomes. So, national income is the sum of rent, interest, profit and wages earned by normal residents of a country during an accounting year.

According to the central statistical organisation (the official agency engaged in the estimation of national income in India) defines national income as under: “National income is the sum of factor income earned by the normal residents of a country in the form of wages, rent, interest and profit in an accounting year.”

Question 6.
Define the functions of Central Bank.
Answer:
Principal function of the central bank are as follows :

1. Issuing of notes : In modem times, central bank alone has the exclusive right to issue notes in every country of the world. The notes, issued by the central bank are unlimited legal tender throughout the country. Central bank of the country enjoys monopoly right of note issuing.
2. Banker to the Government: Central bank acts as a banker, agent and financial advisor to the government. As a banker to the government, it keeps the accounts of all government banks and manages government treasuries. It performs the some functions for the government as the commercial banks do for their customers.
3. Banker’s bank : It performs the function of a banker to all other banks in the country. Central bank has almost the same relation with all other banks as a commercial bank has with its customers. It keeps part of the cash balances of all commercial banks as deposit with a view to meeting liabilities of these banks in times of crisis.
4. Supervision of the banks : As a banker’s bank, the central bank also supervises the commercial banks.
   The supervision of commercial banks relates to
   • licensing of the commercial banks
   • expansion of the commercial banks in terms of their branches across different parts of the country.
5. Lender of the last resort : The central bank also acts as lender of last resort for the other banks of the country. It means that if a commercial bank fails to get financial accommodation form anywhere, it approaches, the central bank as a last resort.

Question 7.
Explain law of demand.
Answer
The law of demand stages that, other things being equal the demand for a good extends with a decrease in price and contracts with an increase in price. There is inverse relationship between quantity demanded of a commodity and its price, provided other factors influencing demand remain unchanged.

The law of demand states that other things remaining constant, quantity demanded of a commodity increases, with a fall,in price and diminishes when price increases.

Question 8.
What do you mean by Macro-economics ?
Answer:
The term Macro in English has its origin in the Greek term Macros which means large. In the context of macro economics “large” means economy as a whole. Thus, macro economic is defined as that branch of economics which studies economic activities at the level of an economy as a whole.

According to M. H. Spencer, “Macro-economics is concerned with the economy as a whole or large segments of it. In Macroeconomics, attention is focused on such problems as the level of unemployment, the rate of inflation, the nation’s total output and other matters of economy-wide significance.”

Question 9.
Explain the functions of money.
Answer:
Functions of money are classified into following two categories:

1. Primary or main functions,
2. Secondary or subsidiary functions.

1. Primary or main functions : This category includes those functions of money, which are common to all countries during all periods.

• Medium of exchange : Medium of exchange is an important function of money. It means that money acts as an intermediary for the goods and services in the exchange transaction. The medium of exchange function of money has classified all transactions on the basis of time and place.
• Measure of value or unit.of value : Unit of account means that the value of each good as service is measured in the monetary unit. Money measures the value of everything or the prices of all goods and services can be expressed in terms of money.

2. Secondary Functions : These functions are supplementary to primary functions. These are as follow.

• Standard of Deferred Payment : Deferred payment means those payments which are to be made in futuse.
• Store of Value : Human beings has a tendancy to save a part of his income for future to fulfil his future requirements. Store of value can take place only when person becomes confident to use his saving as per his requirements in future.
• Transfer of Value : Money is a licuid means of exchange. Hence, purchasing power of money can easirly be transferred from one person to another or one place to the other. Thus, in modem times, money has become the best means of tranferring the value of money.

Question 10.
Write the sources of production.
Answer:
There are five types of the factor of production :

1. Land
2. Labour
3. Capital
4. Organisation
5. Enterprise.

Land, labour, capital, machines tools, equipments and natural means are limited. Every demand of every individual in the economy cannot be satisfied, so the society has to decide what commodieits are to be produced and to what extent. Goods purchased in an economy can be classofied as consumer goods and produce goods. These goods may be further classified as single use goods and durable goods.

It is undoubtedly the basic problem of the economy. If we produce one commodity, it will mean that we are neglecting the production of the other commodity. We assume that all the factors of production in the economy are fully absorbed, so if we want to increase the production of one commodity, we will have to withdraw resources from the production of the other commodity on the basis of 4 requirements goods are further classified as goods for necessaries comforts and luxuries.

Question 11.
Write the Functions of money.
Answer:
Primary function of money are also called prime functions. These functions are of prime importance and common to all countries during all the periods. Money has two primary functions.

1. Medium of exchange : Money acts as a medium of exchange. In modem days, exchange is the basis of entire economy and money makes this exchange possible. At old age barter system was in practise in which goods were exchanged for goods but due to lack of double co¬incidence exchange was difficult. But the uses of money has removed this difficulty. In modem times, money performs all function of exchange in the economy.
2. Measure of value : Money acts unit of measure of value. In other words it acts as a yardstick of standard measures of value to which all other things can be measured. In barter system the general measurement of value was absent and consequently it was difficult to measure the value of exchange. In modem times, the value of every commodity can be measured in money, with the use of money, economic calculations for measuring values have become simplified

Question 12.
What do you mean by NNP ?
Answer:
Net National product at factor cost (NNP_FC) is the sum of total factor income (rent + interest + profit + wages) genrated within the domestic territory of a country along with net factor income from abroad during a year. NNP is the sum of total factor incomes earned.by normal residents of a country during a year.
NDP_FC + Net factor income from abroad = NNP_FC

Question 13.
Explain the importances of Government Budget.
Answer:
The notable objective and importance of government budgets are as follows :

1. Redistribution of income and wealth: Equitable distribution of income and wealth is a sign of social justice which is the principal objective of any welfare state as in India.
2. Reallocation of resources : The government of a country directs the allocation of resources in a manner such that there is a balance between the goals, of profit maximization and social welfare.
3. Economic stability : These refer to the phases of recession, depression, recovery and boom in the economy. Budget is used as an important policy instrument to combat the situations of deflation and inflation. By doing it the government tries to achieve the state of economic stability.
4. Managing public enterprises : The budgetary policy of the government shows interest of the government to increase the rate of growth through public enterprises.

Question 14.
Explain the merits or advantages of perfect competition.
Answer:
The following are the main advantages of. perfect competition:

1. Large number of firms or sellers : The number of firms selling a particular commodity is so large that any increae or decrease in the supply of one particular firm hardly influences the total market supply.
2. Large number of buyers : Not only is the number of sellers very large, also, the number of buyers is very large. Accordingly, like an individual firm, an individual buyer is also not able to influence price of the commodity. Accordingly an individual buyer under perfect competition is also a price taker.
3. Homogeneous product : All sellers sell identical units of a given product. Seeling homogeneous product at the given price rules out the possibility of advertisement or other sale-promotion expenses. So, that there are selling costs, in perfectly competitive market.
4. Perfect knowledge : Buyers and sellers are fully aware of the price prevailing in the market. Buyers know it fully well at what price sellers are selling a given product.
5. Free entry and exit of firms : A firm can enter and leave any industry. There is no legal restriction on the entry or exits.
6. Perfect mobility : Factors, of production are perfectly mobile under perfect competition.

Question 15.
What is GDP ?
Answer:
Gross Domestic Product (GDP) is the market value of the final goods and services produced during a year within the domestic territory of a country.

GDP is the market value of the final goods and services produced within the domestic territory of a country during one year inclusive of depreciation. There are both resident as well as foreign producers within the domestic territory of a country. In India, for example, there are many international banks as well as multinational companies. Gross domestic product includes the market value of the final goods and services produced by all such producers.

Question 16.
Explain the four difficulties of barter exchange.
Answer:
The four difficulties of barter exchange are as follows:

1. Lack of double coincedence : The barter system requires a double coincidence of wants on the parts of those who want to exchange goods or services. It is necessary for a person who wishes to trade his goods or services. It is necessary for a person who wishes to trade his goods or services, but also possesses that goods which the farmer wants.
2. Difficulties in store of value: A major difficulty in barter system appears because store of purchasing power for future can not be made due to perishable nature of most of the goods.
3. Lack of common acceptability unit of value :
   Due to lack of common acceptable unit of value, it becomes difficult to determine. The value of commodity to be exchange for example how will it be determined that how much wheat will be exchanged for are metre of cloth and vice versa.
4. Lack of divisibility in commodities : Another difficulty of barter system relates to the fact that all commodities can not be divided or sub-divided. If the commodity is divided, its utility is lost.

Question 17.
What is law of supply ?
Answer:
The law of supply states that other things remaining constant, quantity supplied of a commodity increases with increase in the price and decreases with a fall in its price.

Law of supply states that, other things remaining constant, there is a positive relationship between price of a commodity and its quantity supplied. Thus, more is supplied at higher price and less at the lower price. There is positive relation between the price and quantity supplied. The law of supply only explain the extension and contraction of supply in response to increase and decrease in price of the commodity. It does not explains increase or decrease in supply.

Supply curve (SS) slopes upward and shows increases in quantity supplied in response to increase in price of the commodity. Thus, quantity supplied increases, when price rises.

Question 18.
Write the advantages of government budget.
Answer:
Advantages of government budget : Budgets plays a decision-making role in planned economy. The goals of economic development in a planned economy may be achieved with the basic instruments of budget. A budget in a planned economy may contain the following advantages.

1. In a planned economy budget is based on the broad objectives of national planning.
2. In initials phase of economic development, planning is supported by deficit budget which is brought to near balanced budget in the later stage of development.
3. In a planned economy a policy of Justice in Taxation is adopted while making budget and for it the policy of progressive taxation is adopted.
4. Budget also plays a positive role in performing the economic activities in the country.

Question 19.
Explain difference between primary and secondary sector.
Answer:
Differences between Primary and Secondary sector are as follows :
Primary Section :

1. It is that sector which exploits natural resources and produce goods and services.
2. It is known as agriculture and allied sector.
3. It includes all agricultural and allied activities such as forestry, mining, quarrying, fishing, animal husbandry etc.
4. Unorganised and traditiona techniques.
5. No possibility of division of labour.

Secondary Sector :

1. It is that sector which transforms one goods into another for creating more utility from it.
2. Famously known as manufacturing sector.
3. It includes manufacturing units, small scale units, large firms, big carporates, multinational corporation.
4. Organised techniques.
5. Complex divisin of labour can be used for production.

Question 20.
Define various types of credits in bank.
Answer:
Principal instruments of monetary policy or credit control of the central bank of a country are broadly classified as:

(a) Quantitative instruments and
(b) Qualitative instruments

(a) Quantitative instruments of monetary policy : There are those instruments of monetary policy which affect supply of money in the economy. These important of monetary policy are as follows :

• Bank rate : The bank rate is the minimum rate at which the central bank of a country (as a lender of last resort) is prepared to give credit to the commercial banks.
• Open market operations : Open market operations refer to the sale and purchase of securities in the open market by the central bank. Cash balances are high powered money on the basis the which commercial banks create credit.

(b) Qualitative Instruments of monetary policy :

• Margin Requirements : The margin requirement of loan refers to the difference between the current value of the security offered for loans and the values of loans granted.
• Rationing of credit: Rationing of credit refers to fixation of credit quotas for different business activities.

Question 21.
What is meant by limitations in Economics ?
Answer:
Economics has classified in two branches :

1. Micioecoomics
2. Macroeconomics

Limitations of Micro economic are as follows : Micro economic analysis fails to adopt the shape of “Universal Analysis” due to its various limitations are as follows:

1. Study not of whole but of a fraction : Micro economics studies only a fraction of a economy and does not study the entire economy. The entire economy can not be represented by studying only individual units.
2. Inadequate analysis : Micro economic analysis is an inadequate analysis because conclusions derived from individual units may not be applicable to entire economy.

Limitations of Macroeconomic are as follows :

1. Macro Economic Paradoxes : Sometimes aggregates provide misleading conclusions. What is true for an individual may not be true for the entire group.
2. Individual units are ignored: Macro economics puts an emphasis on the entire society while individual units, which make the society, are ignored.

Question 22.
What is the difference between Direct tax and Indirect tax.
Answer:
Distinctinction between Direct tax and Indirect tax: .

Direct Taxes :

1. The are directly paid to government by the person on whom it is imposed.
2. They are generally progressive. The rate of tax increase with increase in income.
3. They cannot be shifted on to others.

Indirect Taxes:

1. They are paid to the government by one person but their burden is borne by another person.
2. They are generally regressive. The rate of tax decreases as income increases.
3. They can be shifted on to others.

Question 23.
Explain the functions of commercial banks.
Answer:
The functions of commercial banks are as follows :

(i) Accepting deposits : The prime function of the commercial bank is to accept deposits from bank.
The various types of deposits accepted by the commercial bank are as follows :

• Current Deposits : Deposits in current account are termed as current deposits. A depositer can deposit the amount any member of times he likes and can also withdraw the amount any number of times he wants.
• Saving deposits: Such accounts generally belong to the people having small savings and who do not require withdrawal of money many times.
• Fixed deposits : In fixed accounts, account is deposited for a certain fixed period. Depositor gets deposits receipt while depositing cash in such accounts.
• Recurring deposit : Recurring deposits are certain type of fixed deposit. Depositor deposits certain amount every month in this account.

(ii) Granting loans : The second important primary function of commercial banks is advancing of loans. After keeping certain cash reserves, the banks lend their deposits to needy borrowers.
Various types of loans granted by banks are as follows :

• Cash credit : In cash credit system, bank provides, loans to the borrower against bonds or some other types of securities.
• Overdraft: Customers having current account with the bank are granted the facility of withdrawing more money than the amounts lying in their accounts.
• Loans and advances : A particular, amount is given by banks as loan and advances which is deposited in customer’s account.
• Discounting the bills of exchange : Bank discounts the bill of exchange i.e. after making some marginal deductions, the pays the value of the bill to the holder.
• Investment in government securities : Banks also grant loan to the government. The buying of government securities by banks is termed as ‘Earning to the government:’

(iii) Credit creation : In present times, credit creation has become the prime function of commercial banks. Banks invite primary deposits from the public and grant loan many times than these, priihary deposits on the basis of credit multiplier.

Question 24.
What are main advantages of balance of payments.
Answer:
The main advantages of Balance of Payment are as follows :

1. Systematic record : It is a record of payment and receipts of a country related to its import and export with other country.
2. Fixed period of time : It is amount of a fixed period of time generally a year.
3. Comprehensiveness : It includes all types of visible items invisible items and capital transfer.
4. Double entry system : Payment and receipts are accounted on the basis of double entry system.
5. Self-balanced: Double entry system itself keeps balance of payment as balanced.
6. Adjustment of differences : Whenever difference arises between total receipts and payments, this disequilibrium needs to be adjusted. Balance of payments is thus as overall record of all economic transactions of a country in a given period with rest of the world.

Question 25.
What is Demand ?
Answer:
Demand refers to the quantities of a commodity that the consumers are able and willing to buy at each possible price of the commodity during a given period of time.
The three elements of demand for a commodity :

1. desire for a commodity
2. money to fulfill that desire
3. readiness to spend money.

Thus, demand may be defined as the desire to buy a commodity, backed by sufficient purchasing power and the willingness to spend.

Long Answer Type Questions

Question no. 26 to 33 are Long answer type questions. Answer any 4 of them. Each question carries 5 marks. (4×5 = 20)

Question 26.
Explain the different functions of money.
Answer:
The different functions of money are mainly of two types :

1. Primary functions
2. Secondary functions

1. Primary functions: Primary functions of money are also called prime functions. These functions are of prime importance and common to all countries during all the periods. Money has two prime functions:

• Medium of exchange : Money acts as a
  medium of exchange.In modem days,exchange is the basis of entire economy and money makes this exchange possible.
• Measure of Value : Money acts a unit of measure of value.The value of every commodity can be measured in money.

2. Secondary functions : These functions are supplementary to primary functions.There are following three secondary functions are as follows:

• Standard of deferred payments : Deferred payments mean those payments which are to be made in future.
• Store of value : Store of value can take place only when person becomes confident to use his savings as per his requirements in future.
• Transfer of value : Money is a liquid means of exchange. Hence, purchasing power of money can easily be transferred from one person to another or one place to the other.

Question 27.
Discuss the characteristics of Perfect Competition.
Answer:
Perfect competition.is that market situation in which a large number of buyers and sellers are found for homogeneous product single buyer or the seller are not capable of affecting the prevailing price and hence in a perfect competition market, a single market price prevails for the commodity.
Features of Perfect Competition :

1. Large number of buyers and sellers : Perfect competition market has a large number of buyers and sellers and hence any buyer or seller can not influence the market price. In other words individual buyer or seller can not influence the demand and supply conditions of the market.
2. Homogeneous product: The units sold in the market by all sellers are homogeneous (or identical) in nature.
3. Free entry and exit of firms : In perfect competition any new firm may join the industry or any old firm may quit the industry. Hence there is no restriction on free entry or exit of firms into/from the industry.
4. Perfect knowledge of the market: In perfect competition every buyer has the perfect knowledge of market conditions. None of the buyers will buy the commodity at higher price than the prevailing price in the market. Hence only one price prevails in the market.
5. Perfect mobility of factors : In perfect competition the factors of production are perfectly mobile. Factors can easily be mobile from one industry to other industry (or one firm to another firm) without any difficulty.
6. No transportation cost : Transportation cost remains zero in perfect competition due to which one price prevails in the market.

Question 28.
How does price determination in monopoly ?
Answer:
A monopolist charges, different prices from different consumers, called price discrimination. A monopolist has complete control over price and can also practice price discrimination.

Full control over price under monopoly does not mean monopolist can sell any amount of the commodity at any price. Once the monopolist fixes price of the commodity quantity demanded will entirely depend upon the buyers.

If the buyers feel that price is high, quantity demanded, will be low and vice-versa. Accordingly, there is an inverse . relationship between priede fixed by the monopolist and quantity sold by the monopoly firm or quantity demanded of the monopoly product. Thus, demand curve facing a monopoly firm is downward sloping.

Question 29.
Explain different types of Economic policy.
Answer:
Economic system : It is a structure of such institutions with which all economic activities are operated in the society. Every economy is based on an economic system which can be divided into 3 categories.

1. Capitalist economy or Market economy
2. Socialist economy or Planned economy
3. Mixed economy.

1. Market economy contains the following important features :

• Private property : Capitalist economic system recognises ‘Law of inheritance’ and right of individual private property. It also ensures to transfer the property of dead person to its heir.
• Economic freedom : Capitalist economy grants various economic freedoms to the individual like freedom to work. Freedom of choice of consumption and saving and investment.
• Competition : Competition is an essential features of market. Demand and supply takes places due to competition appearing in the economy.
• Price mechanism : In this economy prices are determined by the automatic adjustment of price mechanism price in market is determined at the point where demand and supply forces become equal.

2. Socialist Economy : The salient features of this economics my all as follows :

• Social ownership : In this economy social ownership is found on factors of production. These factors are used for the welfare of the society as a whole. Right to individual property has no place in socialist economy rather it is profited to only self-consumption goods.
• Passive role of price mechanism : In this economy prices are not determined by price mechanism, rather government take the use of accounting prices which are determined by govt, itself on the basis of social interest.
• Absence of competition : Socialist economy
  works on planning and direction as a result of which competition remains absent in the economy.

3. Mixed Economy : It contains the following economic features:

• Co-existence of private and public ownership : Private and public sectors co-exist in the mixed economy. Both private ownership and profit motive are found in such economic system. Law of inheritance finds a place in the economy but government imposes progressive taxation to attain economic equality.
• Economic freedom : Though enough state interference is found in mixed economy people enjoy limited economics freedom of choice, production investment and saving. Govt, adopts many controls so check the unlimited economic freedom of the individual.
• Price system : Both price mechanism and profit motive determine the price system simultaneously in the
  mixed economy. Profit motive is managed by the govt. So that it may not hit the motive of social welfare.

Question 30.
Explain different process of measurement of national income.
Answer:
Measurement of national income : Three steps of value addition are as follows :
(i) First Step : Identification and classfication of productive enterprise at the very first step, we are to identify and classify various productive enterprises of an economy. Broadly, we can classify the economy into following three sectors:

• Primary sector: It is that sector which produces goods by exploiting natural resources like land, water, forests, mines etc.
• Secondary sector : This sector is also as manufacturing sector. It transforms one type of commodity into another, using men, machines and materials.
• Teritory sector : This sector is also known as service sector, which provides useful services to primary and secondary sector.

(ii) Second Step: Calculation of net value of output To estimate the net value added in each identified
enterprise in step first, the following estimates are calculated:

• Value of output,
• Value of intermediate consumption,
• Consumption of fixed capital i.e. depreciation. Value added + Value of Output – Intermediate consumption- Net Indirect taxes Hence, Net value Value added by Added = Primary sector + value added by secondary sector + value added by teritory sector.

(iii) Third step : Calculation of net factor income – road. The third and final step in the estimation of national income is to estimate the net factor income earned from abroad and add it to the net domestic product at factor.
This gives us the national income.
NNP_FC = NDP_FC + NFIA
Net National Product  Net Domestic product at factor cost = of factor cost
Or, National income + Net factor income from

Question 31.
Define different method of exchange rate?
Answer:
Exchange rate is mainly Of two types are as follows:

1. Fixed exchange rate
2. Flexible exchange rate

1. Fixed rate of exchange refers to that rate of exchange which is fixed by the government. It generally does not change or the changes can take place within a fixed limit only. In gold standard, exchange rate was fixed because changes in exchange rate could take place within certain limits and these limits were called ‘gold points’. Historically the two forms of fixed exchange rate were :

• Gold standard system of exchange rate
• Bretton woods system of exchange rate

2. Flexible exchange rate is that rate which is determined by market forces. Change in flexible exchange rate occur on account of change in market demand and supply. Flexible exchange rate is also called floating exchange rate. Thus, flexible rate is free to fluctuate according to the changes, in the demand and supply of foreign currency.
Hence, R = ∫(D, S)
i .e. Exchange rate is a function of demand and supply.

Question 32.
How many types of credit controlling in central bank ?
Answer:
The two types of credit controlling in central bank are as follows :

1. Quantitative methods
2. Qualitative or Selective methods.

1. Quantitative Method: It refers to those methods of credit control which are used by the central bank to influence the total volume of credit without regard for the purpose for which the credit is put. Quantitaitve credit control methods are :

• Bank rate : The bank rate is the rate of which the central bank is prepared to discount the first class bills of exchanges and grant loans of to commercial banks. This is the indirect important method for controlling credit money.
• Open market operations : Open market operations means “purchase or sale of government and other approved securities by the central bank in money and capital market.”
• Change in cash reserve ratio : When the cash flow or credit is to be increased, cash reserve ratio is reduced and when the cash flow or credit is to be reduced, cash reserve ratio is increased.
• Change in statutory liquidity ratio: Every bank is required to maintain a fix percentage of its assets in the form of cash or other liquid assets, called SLR.

2. Qualitative or Selective method : Qualitative or selective methods are those methods which are used by the central bank to regulate the flow of credit into particular directions of the economy.
The important qualitative methods of credit control are :

• Rationing of credit: Central bank is the lender of last resort. So, it can adopt the measures of credit rationing for credit control.
• Regulation of consumer’s credit : In this method the credit given to durable consumer goods is controlled. In days of inflation, consumer’s credit is squeezed and in days of deflation, credit is expanded.
• Change in margin requirements : Marginal requirement is the difference between the current value of physical security offered for loans and the value of loans granted. Central bank determines marginal requirement ratio for different commodities.
• Direct Action : Central bank can take direct action against any commercial bank if the latter do not follow central banks direction.

Question 33.
Why the slope of demand curve is downward ?
Answer:
Downward slope of demand curve indicated that more is purchased in response to fall in price. It is positive when increase in income causes increase in demand. It occurs in case of normal goods. Income effect is negative when increase in income causes decreases in demand. It occurs in case of inferior, goods, thus, there is inverse relationship between price of a commodity and its quantity demanded. This may be explained in terms of the following factors :

1. Law of diminishing marginal utility: According to this law as a consumer in a given time, increases the consumption of a commodity, the utility from each successive unit goes on diminishing. It is therefore, clear that with fall in price, more units, of a commodity will be demanded and with rise in price, less units, of a commodity will be demanded.
2. Income effect : Income effect is the effect on the change in the quality demanded when the real income of buyer changes as a result of the change in the price of commodity alone.
3. Substitution effect : Substitution effect refers to substitution of one commodity for the other when it becomes relatively cheaper.
4. Size of consumer group :’When the price of a commodity fall many consumer who were not buying it at its previous price begin to purchase it.
5. Different uses : Many goods have alternative uses grams are used for human consumption as well as for the consumption of horses

Bihar Board 12th Physics Objective Questions and Answers

Bihar Board 12th Physics Objective Answers Chapter 3 Current Electricity

Question 1.
1 ampere current is equivalent to
(a) 6.25 × 10¹⁸ electrons s^-1
(b) 2.25 × 10¹⁸ electrons s^-1
(c) 6.25 × 10¹⁴ electrons s^-1
(d) 2.25 × 10¹⁴ electrons s^-1
Answer:
(a) 6.25 × 10¹⁸ electrons s^-1

Question 2.
In an atom electrons revolves around the nucleus along a path of radius 0.72 Å making 9.4 x 10¹⁸ revolution per second. The equivalent current is
(e = 1.6 × 10^-19 C)
(a) 1.2 A
(b) 1.5 A
(c) 1.4 A
(d) 1.8 A
Answer:
(b) 1.5 A

Question 3.
The direction of the flow of current through electric circuit is
(a) from low potential to high potential.
(b) from high potential to low potential.
(c) does not depend upon potential value.
(d) current cannot flow through circuit.
Answer:
(b) from high potential to low potential.

Question 4.
The electrical resistance of a conductor depends upon
(a) size of conductor
(b) temperature of conductor
(c) geometry of conductor
(d) all of these
Answer:
(d) all of these

Question 5.
A wire of resistance 4Ω is used to wind a coil of radius 7 cm. The wire has a diameter of 1.4 mm and the specific resistance of its material is 2 × 10^-7 Ω m. The number of turns in the coil is
(a) 50
(b) 40
(c) 60
(d) 70
Answer:
(d) 70
Solution:
(d) Let n be the number of turns in the coil.
Then total length of wire used,

Question 6.
Space between two concentric spheres of radii r₁ and r₂, such that r₁ < r₂, is filled with a material of resistivity ρ . Find the resistance between inner and outer surface of the material.

Answer:
(b) \(\frac{r_{2}-r_{1}}{r_{1} r_{2}} \frac{\rho}{4 \pi}\)
Solution:

Question 7.
The I-V characteristic shown in figure represents
(a) ohmic conductors
(b) non-ohmic conductors
(c) insulators
(d) superconductors
Answer:
(b) non-ohmic conductors

Question 8.
Range of resistivity for metals is
(a) 10^-6 Ω m to 10^-4 Ω m
(b) 10^-7 Ω m to 10^-5 Ω m
(c) 10^-8 Ω m to 10^-6 Ω m
(d) 10^-9 Ω m to 10^-7 Ω m
Answer:
(c) 10^-8 Ω m to 10^-6 Ω m

Question 9.
Wire bound resistors are made by
(a) winding the wires of an alloy viz, Cu, Al, Ag
(b) winding the wires of an alloy viz, Si, Tu, Fe
(c) winding the wires of an alloy viz, Ge, Au, Gr
(d) winding the wires of an alloy viz, manganin, constantan, nichrome.
Answer:
(d) winding the wires of an alloy viz, manganin, constantan, nichrome.

Question 10.
The resistivity of alloy manganin is
(a) Nearly independent of temperature
(b) Increases rapidly with increase in temperature
(c) Decreases with increase in temperature
(d) Increases rapidly with decrease in temperature
Answer:
(a) Nearly independent of temperature

Question 11.
What is the order of magnitude of the resistance of a dry human body ?
(a) 10 Ω
(b) 10 KΩ
(c) 10 MΩ
(d) 10 μΩ
Answer:
(b) 10 KΩ

Question 12.
Two copper wires of length l and 21 have radii, r and 2r respectively. What is the ratio of their specific resistances ?
(a) 1 : 2
(b) 2 : 1
(c) 1 : 1
(d) 1 : 3
Answer:
(c) 1:1

Question 13.
Nichrome or Manganin is widely used in wire bound standard resistors because of their
(a) temperature independent resistivity
(b) very weak temperature dependent resistivity
(c) strong dependence of resistivity with temperature
(d) mechanical strength
Answer:
(b) very weak temperature dependent resistivity

Question 14.
An electric heater is connected to the voltage supply. After few seconds, current get its steady value then its initial current will be
(a) equal to its steady current
(b) slightly higher than its steady current
(c) slightly less than its steady current
(d) zero
Answer:
(b) slightly higher than its steady current

Question 15.
In the circuit shown in figure heat developed across 2 Ω,4 Ω and 3 Ωresistances are in the ratio of

(a) 2 : 4 : 3
(b) 8 : 4 : 12
(c) 4 : 8 : 27
(d) 8 : 4 : 27
Answer:
(d) 8 : 4 : 27

Question 16.
The total resistance in the parallel combination of three resistances 9 Ω,7 Ω, and 5Ω is
(a) 1.22 Ω
(b) 2.29 Ω
(c) 4.22 Ω
(d) 2.02 Ω
Answer:
(d) 2.02 Ω
Solution:
(d) In the parallel combination of three resistances, the equivalent resistance is

Question 17.
Five equal resistances of 10 £2 are connected between A and B as shown in figure. The resultant resistance

(a) 10Ω
(b) 5Ω
(c) 15Ω
(d) 6Ω
Answre:
(b) 5Ω
Solution:
(b) According to the given circuit 10 Ω and 10 Ω resistances are connected in series.
∴ R’= 10 + 10 = 20Ω
Again 10 Ω and 10Ω resistances are connected in series
∴R”= 10 + 10 = 20 Ω
R’, R” and 10 Ω all connected in parallel than

Question 18.
A copper cylindrical tube has inner radius a and outer radius b. The resistivity is P. The resistance of the cylinder between the two ends is

Answer:
(c) \(\frac{\rho^{f}}{\pi\left(b^{2}-a^{2}\right)}\)

Question 19.
A and B are two points on a uniform ring of resistance 15Ω . The ∠AOB = 45°. The equivalent resistance between A and B is

(a) 1.64 Ω
(b) 2.84 Ω
(c) 4.57 Ω
(d) 2.64 Ω
Answer:
(a) 1.64 Ω

Question 20.
The reading of ammeter shown in figure is

(a) 6.56 A
(b) 3.28 A
(c) 2.18 A
(d) 1.09 A
Answer:
(d) 1.09 A

Question 21.
In a circuit a cell with internal resistance r is connected to an external resistance R. The condition for the maximum current that drawn from the cell is
(a) R = r
(b) R < r
(c) R > r
(d) R = 0
Answer:
(d) R = 0

Question 22.
In parallel combination of n cells, we obtain
(a) more voltage
(b) more current
(c) less voltage
(d) less current
Answer:
(b) more current

Question 23.
If n cells each of emf e and internal resistance r are connected in parallel, then the total emf and internal resistances will be

Answer:
(a) \(\varepsilon, \frac{\mathrm{r}}{\mathrm{n}}\)

Question 24.
The potential difference between A and B as shown in figure is

(a) 1 V
(b) 2 V
(c) 3 V
(d) 4 V
Answer:
(a) 1 V
Solution:
(a) Resistance of the upper arm CAD = 2 Ω +3 Ω = 5 Ω
Resistance of the lower arm CBD = 3 Ω +2 Ω =5 Ω

As the resistance of both arms are equal, therefore same amount of current flows in both the arms. Current through each arm CAD or CBD = 1A

Potential difference across C and A is
V_C – V_B = (2Ω) (1 A)
= 2 V …..(i)
Potential difference across C and B is
V_C – V_B = (3Ω) (1 A)
= 3 V ………..(ii)
Subtracting (i) from (ii), we get V_A – V_B = 3V – 2V = 1V

Question 25.
In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will
(a) change in previous direction
(b) not change
(c) change in opposite direction
(d) none of these
Answer:
(b) not change

Question 26.
In a Wheatstone’s network, P = 2Ω, Q = 2Ω, R = 2Ω, and S = 3Ω The resistance with which S is to be shunted in order that the bridge may be balanced is
(a) 1Ω
(b) 2Ω
(c) 4Ω
(d) 6Ω
Answer:
(d) 6Ω
Solution:
(d) Let x be the resistance shunted with S for the bridge to be balanced.
For a balance Wheatone’s bridge

Question 27.
When a metal conductor connected to left gap of a meter bridge is heated, the balancing point
(a) shifts towards right
(b) shifts towards left
(c) remains unchanged
(d) remains at zero
Answer:
(a) shifts towards right

Question 28.
In a meter bridge experiment, the ratio of the left gap resistance to right gap resistance is 2 : 3, the balance point from left is
(a) 60 cm
(b) 50 cm
(c) 40 cm
(d) 20 cm
Answer:
(c) 40 cm
Solution:

Question 29.
Which of the following characteristics of electrons determines the current in a conductor ?
(a) Drift velocity alone
(b) Thermal velocity alone
(c) Both drift velocity and thermal velocity
(d) Neither drift not thermal velocity
Answer:
(a) Drift velocity alone

Bihar Board 12th Chemistry Objective Questions and Answers

Bihar Board 12th Chemistry Objective Answers Chapter 3 Electrochemistry

Question 1.
Which of the following is the correct cell representation for the given cell reaction ?
Zn + H₂SO₄→ ZnSO₄ + H₂
(a) Zn|Zn²⁺||H ⁺ |H₂
(b) Zn|Zn²⁺||H ⁺ ,H₂|Pt
(c) Zn |ZnSO₄| |H₂SO₄| Zn
(d) Zn |H₂SO₄||ZnSO₄| H₂
Answer:
(b) Zn|Zn²⁺||H ⁺ ,H₂|Pt

Question 2.
The cell reaction of the galvanic cell:

(a) Hg + Cu²⁺→ Hg²⁺+Cu
(b) Hg + Cu²⁺→ Cu⁺Hg⁺
(c) Cu + Hg → CuHg
(d) Cu + Hg²⁺→ Cu²⁺ Hg
Answer:
(d) Cu + Hg²⁺→ Cu²⁺ Hg

Question 3.
Which of the following reaction is possible at anode ?
(a) 2Cr³⁺ +7H₂O → Cr₂O₇^2- + 14H⁺
(b) F₂ → 2F^–
(c) (1/2)O₂ +2H⁺ → H₂O
(d) None of these.
Answer:
(a) 2Cr³⁺ +7H₂O → Cr₂O₇^2- + 14H⁺

Question 4.
In the cell, |Zn²⁺| |Cu²⁺|Cu, the negative terminals ………..
(a) Cu
(b) Cu²⁺
(c) Zn
(d) Zn²⁺
Answer:
(c) Zn

Question 5.
In a cell reaction,

If the concentration of Cu²⁺ ions is doubled then Eº_Cell will be
(a) doubled
(b) halved
(c) increased by four times
(d) unchanged
Answer:
(d) unchanged

Question 6.
A standard hydrogen electrode that a zero potential because ……………..
(a) hydrogen can be most’easily oxidised
(b) hydrogen has only one electron
(c) the electrode potential is assumed to be zero
(d) hydrogen is the lightest element.
Answer:
(c) the electrode potential is assumed to be zero

Question 7.
Which of the following is the correct order in which metals displace each other from the salt solution of their salts  ?
(a) Zn, Al, Mg, Fe, Cu
(b) Cu, Fe, Mg, Al, Zn
(c) Mg, Al, Zn, Fe, Cu
(d) Al, Mg, Fe, Cu, Zn
Answer:
(d) Al, Mg, Fe, Cu, Zn

Question 8.
Fluorine is the best oxidising agent because it has ………..
(a) highest electron affinity
(b) highest reduction potential
(c) highest oxidation potential
(d) lowest electron affinity.
Answer:
(b) highest reduction potential

Question 9.
At 25°C, Nemst equation is …………..

Answer:
(a)

Question 10.
The correct Nernst equation for the given cell

Answer:

Question 11.
What will be the emf of the following concentration cell at 25°C ?
Ag_(s)| AgNO₃(0.01M)| | AgNO₃(0.05M)| Ag_(s)
(a) 0.828 V
(b) 0.0413 V
(c) -0.0413 V
(d) -0.828 V
Answer:
(b) 0.0413 V

Question 12.
What will be the reduction potential for the following half-cell reaction at 298 K ? [Given: [Ag⁺] = 0.1 M and
E°_e„ = +0.80 V)] ………….
(a) 0.741V
(b) 0.80 V
(c) -0.80 V
(d) -0.741V
Answer:
(a) 0.741V

Question 13.
For the cell reaction: 2Cu_(aq) → Cu_(s) + Cu²⁺ the standard ceil potential is 0.36 V. The equilibrium constant for the reaction is ………….
(a) 1.2 x 10⁶
(b) 7.4 x 10¹²
(c) 2.4 x 10⁶
(d) 5.5 x 10⁸
Answer:
(a) 1.2 x 10⁶

Question 14.
E°_cell for the reaction, 2H₂O^–+ H₃O⁺ + OH” at 25°C is -0.8277 V. The equilibrium constant for the reaction is ………….
(a) 10^-14
(b) 10^-23
(c) 10^-7
(d) 10^-21
Answer:
(a) 10^-14

Question 15.
Cell reaction is spontaneous, when …………….
(a) E°_d is negative
(b) ΔG° is negative
(c) E°_oxid is positive
(d) ΔG° is positive
Answer:
(b) ΔG° is negative

Question 16.
ΔG° f°^r the reaction, Cu²⁺+ Fe → Fe²⁺ + Cu is

(a) 11.44 kJ
(b) 180.8 kJ
(c) 150.5 kJ
(d) 28.5 kJ
Answer:
(c) 150.5 kJ

Question 17.
Units of the properties measured are given below. Which of the properties has not been matched correctly ?
(a) Molar conductance = S m² mol^-1
(b) Cell constant = m^-1
(c) Specific conductance = S m²
(d) Equivalent conductance = S m² (g eq)^-1
Answer:
(c) Specific conductance = S m²

Question 18.
Molar conductivity of 0.15 M solution of KCl at 298 K, if its conductivity is 0.0152 S cm^-1 will be
(a) 124 Ω^-1 cm²    mol^-1
(b) 204  Ω^-1 cm² mol^-1
(c) 101 Ω^-1 cm² mol^-1
(d) 300  Ω^-1 cm² mol^-1
Answer:
(c) 101 Ω^-1 cm²   mol^-1

Question 19.
The molar conductivity is maximum for the solution of concentration
(a) 0.004 M
(b) 0.002 M
(c) 0.005 M
(d) 0.001 M
Answer:
(d) 0.001 M

Question 20.
Specific conductance of 0.1 M NaCl solution is 1.01 x 10^-2 ohm^-1 cm^-1. Its molar conductance in ohm^-1 cm² mol^-1
(a) 1.01 x 10²
(b) 1.01 x 10³
(c) 1.01 x 10⁴
(d) 1.01
Answer:
(a) 1.01 x 10²

Question 21.
When water is added to an aqueous solution of an electrolyte, what is the change in specific conductivity of the electrolyte ?
(a) Conductivity decreases
(b) Conductivity increases
(c) Conductivity remain same
(d) Conductivity does not depend on number of ions
Answer:
(a) Conductivity decreases

Question 22.
Mark the correct choice of electrolytes represented in the graph.

(a) A → 4 NH₄OH, B → NaCl
(b) A →NH₄OH,B → NH₄Cl
(c) A → CH₃COOH, B → 4CH₃COONa
(d) A → KCl, B → 4 NH₄OH
Answer:
(d) A → KCl, B → 4 NH₄OH

Question 23.
Molar conductivity of NH₄OH can be calculated by the equation,

Answer:
(c)

Question 24.
Limiting molar conductivity of NaBr is
(a) Δ°_mNaBr = Δ°_mNaCl + Δ°_mKBr
(b) Δ°_mNaBr = Δ°_mNaCl + Δ°_mKBr – Δ°_mKCl
(c) Δ°_mNaBr = Δ°_mNaOH + Δ°_mNaBr – Δ°_mNaCl
(d) Δ°_mNaBr = Δ°_mNaCl – Δ°_mNaBr
Answer:
(b) Δ°_mNaBr = Δ°_mNaCl + Δ°_mKBr – Δ°_mKCl

Question 25.
Δ°_m(NH₄OH) is equal to …………..
(a) Δ°_{m (NH4OH)} + Δ°_{m (NH4a) –}  -Δ°_m(HCl)
(b) Δ°_m(NH4Cl) + Δ°_{m (NaOH) –} Δ°_m(Nao)
(c) Δ°_m(NH₄Cl) + Δ°_m(NaCl) –  Δ°_m(NaOH)
(d) Δ°_m(NaOH) +Δ°_m(NaCI) – Δ°_m(NH₄Cl)
Answer:
(b) Δ°_m(NH4Cl) + Δ°_{m (NaOH) –} Δ°_m(Naa)

Question 26.
In an electrolytic cell, the flow of electrons is
(a) from cathode to anode in the solution
(b) from cathode to anode through external supply
(c) from cathode to anode through internal supply
(d) from anode to cathode through internal supply.
Answer:
(c) from cathode to anode through internal supply

Question 27.
How long would it take to deposit 50 g of Ai from an electrolytic cell containing Al₂O₃ using a current of 105 ampere
(a) 54 h
(b) 1.42 h
(c) 32 h
(d) 2.15 h
Answer:
(b) 1.42 h

Question 28.
The charge required for reducing 1 mole of MnO₄ to Mn²⁺ is ……………….
(a) 93 x 10⁵ C
(b) 2.895 x  10⁵ C
(c) 4.28 x  10⁵ C
(d) 4.825 x  10⁵ C
Answer:
(d) 4.825 x  10⁵ C

Question 29.
How much electricity in terms of Faraday is required to  produce 100 g of Ca from molten CaCl₂ ?
(a) IF
(b) 2F
(c) 3 F
(d) 5F
Answer:
(a) IF

Question 30.
How many coulombs of electricity is required to reduce 1 mole of Cr₂O² in acidic medium ?
(a) 4 x  96500C
(b) 6 x  96500 C
(c) 2 x 96500 C
(d) 1 x  96500 C
Answer:
(b) 6 x  96500 C

Question 31.
How much metal will be deposited when a current of 12 ampere with 75% efficiency is passed through the cell for 3 h ? (Given : Z = 4 x 10^-4)
(a) 32.4 g
(b) 38.8 g
(c) 0 g
(d) 22.4 g
Answer:
(b) 38.8 g

Question 32.
How many moles of Pt may be deposited on the cathode when 0.80 F of electricity is passed through a 1.0 M solution of Pt⁴⁺ ?
(a) 0.1 mol
(b) 0.2  mol
(c) 4 mol
(d) 0.6  mol
Answer:
(b) 0.2  mol
(b) Pt⁴⁺ + 4e^– → Pt
4 moles of electricity or 4 F of electricity is required to deposit 1 mole of Pt.
0. 80 F of electricity will deposit
\(\frac{1}{4}\) 0.80 = 0.20 mol

Question 33.
If 54 g of silver is deposited during an electrolysis reaction, how much aluminium will be deposited by the same amount of electric current ?
(a) 2.7 g
(b) 4.5  g
(c) 27 g
(d) 5.4  g
Answer:
(b) 4.5g

Question 34.
During the electrolysis of dilute sulphuric acid, the following process is possible at anode.

Answer:
(a)

Question 35.
When a lead storage battery is discharged,
(a) lead sulphate is consumed
(b) oxygen gas is evolved
(c) lead sulphate is formed
(d) lead sulphide is formed.
Answer:
(c) lead sulphate is formed

Question 36.
The reaction which is taking place in nickel-cadmium battery can be represented by which of the following equation
(a) Cd + NiO₂ + 2H₂O → 4 Cd(OH)₂ + Ni(OH)₂
(b) Cd + NiO₂ + 2 OH⁺ → Ni + Cd(OH)₂
(c) Ni + Cd(OH)₂ → Cd + Ni(OH)₂
(d) Ni(OH)₂ +Cd(OH)₂ → Ni + Cd + 2H₂O
Answer:
(a) Cd + NiO₂ + 2H₂O → 4 Cd(OH)₂ + Ni(OH)₂

Question 37.
Which of the following reactions does not take place during rusting ?
(a) 4₂ CO₃ 2H⁺ + CO⁺
(b) 4Fe²⁺ + O_2(dry) → Fe₂O₃
(c) 4Fe²⁺ +O₂ +4H₂O → 2Fe₂O₃ +8H⁺
(d) Fe₂O₃ + xH₂O → Fe₂O₃. x H₂O
Answer:
(a) 4₂ CO₃ 2H⁺ + CO⁺

Question 38.
Which of the following reactions does not take place during rusting ?
(a)

(b) 4Fe²⁺ + O_2(dry) → Fe₂O₃
(c) 4Fe²⁺ + O₂ +4H₂O → 2Fe₂O₃ +8H⁺
(d) Fe₂O₃ + xH₂O → Fe₂O₃. xH₂O
Answer:
(b) 4Fe²⁺ + O_2(dry) → Fe₂O₃

Question 39.
The difference between the electrode potentials of two electrodes when no current is drawn through the cell is called
(a) cell potential
(b) cell emf
(c) potential difference
(d) cell voltage
Answer:
(b) cell emf

Question 40.
An electrochemical cell can behave like an electrolytic cell when ___
(a) ^Ecell = 0
(b) E_{cell >} E_ext
(c) E_{extl >} E_cell
(d) E_cell = E_ext
Answer:
(c) E_{extl >} E_cell

Question 41.
Use the data given in Q. 61 and find out the most stable ion in its reduced form.
(a) Cl-
(b) Cr³⁺
(c) Cr
(d) Mn²⁺
Answer:
(d) Mn²⁺

Question 42.
Use the data of Q. 61 and find out the most stable oxidised species…….
(a) Cr³⁺
(b) MnO₄
(c) Cr₂O^2-
(d) Mn²⁺
Answer:
(a) Cr³⁺

Question 43.
The quantity of charge required to obtain one mole of aluminium from Al₂O₃ is____________
(a) 1F
(b) 6F
(c) 3F
(d) 2F
Answer:
(c) 3F

Question 44.
The cell constant of a conductivity cell_____________
(a) changes with change of electrolyte
(b) changes with change of concentration of electrolyte
(c) changes with temperature of electrolyte
(d) remains constant for a cell
Answer:
(d) remains constant for a cell

Question 45.
While charging the lead storage battery___________
(a) PbSO₄ anode is reduced to Pb
(b) PbSO₄ cathode is reduced to Pb
(c) PbSO₄ cathode is oxidised to Pb
(d) PbSO₄ anode is oxidised to PbO₂
Answer:
(a) PbSO₄ anode is reduced to Pb

Bihar Board 12th Physics Objective Questions and Answers

Bihar Board 12th Physics Objective Answers Chapter 15 Communication Systems

Question 1.
Who invented world wide web?
(a) J.C.R. Licklider
(b) Tim Berners-Lee
(c) Alexander Graham Bell
(d) Samuel F.B. Morse
Answer:
(b) Tim Berners-Lee

Question 2.
Essential elements of a communication system are
(a) transmitter and receiver
(b) receiver and communication channel
(c) transmitter and communication channel
(d) transmitter, communication channel and receiver
Answer:
(d) transmitter, communication channel and receiver

Question 3.
Which of the following is an example of point to point communication mode?
(a) Radio
(b) Television
(c) Telephony
(d) All of these
Answer:
(c) Telephony

Question 4.
Which among the following is not a basic terminology used in electronic communication systems?
(a) Transducer
(b) Transmitter
(c) Telegraph
(d) Attenuation
Answer:
(c) Telegraph

Question 5.
Which of the following is not a transducer?
(a) Loudspeaker
(b) Amplifier
(c) Microphone
(d) All of these
Answer:
(b) Amplifier

Question 6.
The loss of strength of a signal while propagating through a medium is known as
(a) reception
(b) absorption
(c) transmission
(d) attenuation
Answer:
(d) attenuation

Question 7.
The process of increasing the strenth of a signal using an electronic circuit is called
(a) amplification
(b) modulation
(c) demodulation
(d) transmission
Answer:
(a) amplification

Question 8.
Modem is a device which performs
(a) modulation
(b) demodulation
(c) rectification
(d) modulation and demodulation
Answer:
(d) modulation and demodulation

Question 9.
Modulation is the process of superposing
(a) low frequency audio signal on high frequency radio waves
(b) low frequency radio signals on low frequency audio . wave
(c) high frequency radio signal on low frequency audio signal
(d) high frequency audio signal on low frequency radio waves
Answer:
(a) low frequency audio signal on high frequency radio waves

Question 10.
The device which is a combination of a receiver and a transmitter is
(a) Amplifier
(b) Repeater
(c) Transducer
(d) Modulator
Answer:
(b) Repeater

Question 11.
Large bandwidth for higher data rate is achieved by using
(a) high frequency carrier wave
(b) high frequency audio wave
(c) low frequency carrier wave
(d) low frequency audio wave
Answer:
(a) high frequency carrier wave

Question 12.
In a video signal for transmission of picture, what value of bandwidth used in communication system?
(a) 2.4 MHz
(b) 4.2 MHz
(c) 24 MHz
(d) 42 MHz
Answer:
(b) 4.2 MHz

Question 13.
Which of the following is an example of broadcast mode of communication?
(a) Radio
(b) Television
(c) Mobile
(d) Both (a) & (b)
Answer:
(d) Both (a) & (b)

Question 14.
Which of the following devices is full duplex?
(a) Mobile phone
(b) Walky-talky
(c) Loud speaker
(d) Radio
Answer:
(a) Mobile phone

Question 15.
FM broadcast is preferred over AM broadcast becuase
(a) it is less noisy
(b) reproduction is of much better quality
(c) it is more noisy
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

Question 16.
The frequency band used in the downlink of satellite communication is
(a) 9.5 to 2.5 GHz
(b) 896 to 901 MHz
(c) 3.7 to 4.2 GHz
(d) 840 to 935 MHz
Answer:
(c) 3.7 to 4.2 GHz

Question 17.
The radio waves of frequency 30 MHz to 300 MHz belong to
(a) high frequency band
(b) very high frequency band
(c) ultra high frequency band
(d) super high frequency band
Answer:
(b) very high frequency band

Question 18.
Ground waves have wavelength
(a) less than that of sky waves
(b) greater than that of sky waves
(c) less than that of space waves
(d) equal to that of space waves
Answer:
(b) greater than that of sky waves

Question 19.
The mode of propagation used by short wave broadcast services is
(a) space wave
(b) sky wave
(c) ground wave
(d) both (a) and (c)
Answer:
(b) sky wave

Question 20.
The skip zone in radio wave transmission is that range where
(a) there is no reception of either ground wave or sky wave
(b) the reception of ground-wave is maximum but that of sky wave is minimum
(c) the reception of ground wave is minimum, but that of sky wave is maximum
(d) the reception of both ground and sky wave is maximum
Answer:
(a) there is no reception of either ground wave or sky wave

Question 21.
The waves that are bent down by the ionosphere are
(a) ground waves
(b) surface waves
(c) space waves
(d) sky waves
Answer:
(d) sky waves

Question 22.
The maximum line-of-sight distance d_M between two antennas having heights h_T and h_R above the earth is

Answer:
(d)

Question 23.
Frequencies in the UHF range normally propagate by means of
(a) ground waves
(b) sky waves
(c) surface waves
(d) space waves
Answer:
(d) space waves

Question 24.
A ground reciver in line-of-sight communication cannot receive direct waves due to
(a) its low frequency
(b) curvature of earth
(c) its high intensity
(d) smaller antenna
Answer:
(b) curvature of earth

Question 25.
Which of the following modes is used for line of sight communication as well as satellite communication?
(a) Ground wave
(b) Sky wave
(c) Space wave
(d) All of these
Answer:
(c) Space wave

Question 26.
Through which mode of propagation, the radio waves can be sent from one place to another
(a) ground wave propagation
(b) sky wave propagation
(c) space wave propagation
(d) all of them
Answer:
(d) all of them

Question 27.
Which of the following frequency will be suitable for beyond the horizon communication using sky waves?
(a) 10 kHz
(b) 10 MHz
(c) 1 GHz
(d) 1000 GHz
Answer:
(b) 10 MHz

Question 28.
What should be the length of the dipole antenna for a carrier wave of frequency 3 x 10⁸ Hz?
(a) 1 m
(b) 0.5 m
(c) 2 m
(d) 2.5 m
Answer:
(b) 0.5 m

Question 29.
A radio can tune to any station in 7.5 MHz to 12 MHz band. The corresponding wavelength band is
(a) 25 m-40m
(b) 10 m-30m
(c) 20-40 m
(d) 25 m – 35 m
Answer:
(a) 25 m-40m

Question 30.
In frequency modulation
(a) the amplitude of modulated wave varies as frequency of carrier wave
(b) the frequency of modulated wave varies as amplitude of modulating wave
(c) the amplitude of modulated wave varies as amplitude of carrier wave
(d) the frequency of modulated wave varies as frequency of modulating wave
Answer:
(d) the frequency of modulated wave varies as frequency of modulating wave

Question 31.
Audio signal cannot be transmitted because
(a) the signal has more noise.
(b) the signal cannot be amplified for distance communication.
(c) the transmitting antenna length is very small to design.
(d) the transmitting antenna length is very large and impracticable.
Answer:
(d) the transmitting antenna length is very large and impracticable.

Question 32.
The modulation in which pulse duration varies in accordance with the modulating signal is called
(a) PAM
(b) PPM
(c) PWM
(d) PCM
Answer:
(c) PWM

Question 33.
A 300 W carrier is modulated to a depth 75%. The total power in the modulated wave is
(a) 200 W
(b) 284 W
(c) 320 W
(d) 384 W
Answer:
(d) 384 W

Question 34.
A signal wave of frequency 12 kHz is modulated with a carrier wave of frequency 2.51 MHz. The upper and lower side band frequencies are respectively
(a) 2512 kHz and 2508 kHz
(b) 2522 kHz and 2488 kHz
(c) 2502 kHz and 2498 kHz
(d) 2522 kHz and 2498 kHz
Answer:
(d) 2522 kHz and 2498 kHz

Question 35.
The maximum amplitude of an amplitude modulated wave is found to be 15 V while its minimum amplitude is found to be 3 V. The modulation index is
\((a) \frac{3}{2}
(b) \frac{2}{3}
(c) \frac{1}{2}
(d) \frac{1}{3}\)
Answer:
\((b) \frac{2}{3}\)

Question 36.
The LC product of a tuned amplifier circuit require to generate a carrrier wave of 1 MHz for amplitude modulation is
(a) 1.5 x 10^-14 s
(b) 1.2 x 10^-12 s
(c) 3.2 x 10^-12 s
(d) 2.5 x 10^-14 s
Answer:
(d) 2.5 x 10^-14 s

Question 37.
The essential condition for demodulation is

Answer:
(b)

Question 38.
Figure shows a communication system. What is the output power when input signal is 1.01 m W?

(a) 90 mW
(b) 101 mW
(c) 112 m W
(d) 120 mW
Answer:
(b) 101 mW

Question 39.
A 100 m long antenna is mounted on a 500 m tall building. The complex can become a transmission tower for waves with X
(a) ~ 400 m
(b)~25m
(c)~150m
(d)~ 2400 m
Answer:
(a) ~ 400 m

Question 40.
A male voice after modulation-transmission sounds like that of a female to the receiver. The problem is due to
(a) poor selection of modulation index (selected 0<w<l)
(b) poor bandwidth selection of amplifiers
(c) poor selection of carrier frequency
(d) loss of energy in transmission
Answer:
(b) poor bandwidth selection of amplifiers

Question 41.
A basic communication system consists of
(A) transmitter
(B) information source
(C) user of information
(D) channel
(E) receiver

Choose the correct sequence in which these are arranged in a basic communication system.
(a) ABCDE
(b) BADEC
(c) BDACE
(d) BEADC
Answer:
(b) BADEC

Question 42.
Identify the mathematical expression for amplitude modulated wave.
\( (a) A_{c} \sin \left[\left\{\omega_{c}+k_{1} v_{m}(t)\right\} t+\phi\right]\)
\( (b) A_{c} \sin \left\{\omega_{c} t+\phi+k_{2} v_{m}(t)\right\}\)
\( (c) \left\{A_{c}+k_{2} v_{m}(t)\right\} \sin \left(\omega_{n} t+\phi\right)\)
\( (d) A_{c} v_{m}(t) \sin \left(\omega_{c} t+\phi\right)\)
Answer:
\((c) \left\{A_{c}+k_{2} v_{m}(t)\right\} \sin \left(\omega_{n} t+\phi\right)\)

Hints And Explanations

Question 29.
(a) Wavelength corresponding to 7.5 MHz frequency
Answer:
\(\lambda_{1}=\frac{c}{v}=\frac{3 \times 10^{8}}{7.5 \times 10^{6}}=40 \mathrm{m}\)
Wavelength corresponding to 12 MHz frequency
\(\lambda_{2}=\frac{3 \times 10^{8}}{12 \times 10^{6}}=25 \mathrm{m}\)

Question 33.
P_c = 300 W, μ, = 75% = 0.75
Answer:

Question35.
(b) Here, A_c + A_m = 15 V …………………. (i)
A_c – A_m = 3V ………………………… (ii)
Answer:
Solving (I) and (ii), we get, A_c =9 V, A_m = 6 V
∴ Modulation index, \(\mu=\frac{A_{m}}{A_{c}}=\frac{6}{9}=\frac{2}{3}\)

Question 36.
(d) Frequency of tuned amplifier is \(v=\frac{1}{2 \pi \sqrt{L C}}\)
Answer:
As per question, u = 1 MHz = 10⁶ Hz

Question 38.

Answer:
Here, transmission path = 5 km
Loss suffered in transmission path
= – 2 dB km^-1 x 5 km = – 10 dB
Total amplifier gain = 10 dB + 20 dB = 30 dB
Overall gain of signal = 30 dB – 10 dB = 20 dB

Question 39.
(a) Length of antenna, ¡ = 100 m,
As l = \(\frac{\lambda}{4}\) or λ = 4l = 4 x 100 = 400m.

Very Important Questions

Question 1.
The electric Held at a point near an infinite thin sheet of charged conductor is :

Answer:
(c)

Question 2.
Two capacitors C₁ = 2μF and C₂ = 4μF are connected in series and a potential difference (p.d.) of 1200 V is applied across it. The Potential difference across 2μF will be :
(a) 400 V
(b) 600 V
(c) 800V
(d) 900V
Answer:
(c) 800V

Question 3.
In the figure, ifnet force on Q is zero then value of \(\frac{Q}{q}\) is:

Answer:
(b)

Question 4.
When a body is charged, its mass
(a) increases
(b) decreases
(c) remains same
(d) may increase or decrease
Answer:
(d) may increase or decrease

Question 5.
The electric potential due to a small electric dipole at a large distance r from the center of the dipole is proportional to :
\((a) r
(b) \frac{1}{r}
(c) \frac{1}{r^{2}}
(d) \frac{1}{r^{3}}\)
Answer:
\((c) \frac{1}{r^{2}}\)

Question 6.
Minimum number of capacitors of 2pF each required to obtain a capacitance of 5fxF will be
(a) 4
(b) 3
(c) 5
(d) 6
Answer:
(a) 4

Question 7.
The specific resistance of conductor increases with :
(a) increase of temperature
(b) increase of cross-sectional area
(c) decrease in length
(d) decrease of cross-sectional area
Answer:
(a) increase of temperature

Question 8.
The Drift velocity (vd) and applied electric field (E) of a conductor are related as :
\((a) \mathrm{V}_{\mathrm{d}} \propto \sqrt{\mathrm{E}}
(b) \mathrm{V}_{\mathrm{d}} \propto \mathrm{E}
(c) \mathrm{V}_{\mathrm{d}} \propto \mathrm{E}^{2}
(d) v_{d}= Constant\)
Answer:
\((b) \mathrm{V}_{\mathrm{d}} \propto \mathrm{E}\)

Question 9.
A charge ‘q’ moves in a region where electric field ‘E’ and magnetic field ‘B’ both exist, then force on it is :

Answer:
(b)

Question 10.
A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of either part is :
(a) M
(b) M/2
(c) 2M
(d) Zero
Answer:
(b) M/2

Question 11.
The dimensional formula for \(\frac{1}{2} \varepsilon_{0} \mathbf{E}^{2}\) is identical to that of:

Answer:
(a)

Question 12.
A circular coil of radius R carries a current I. The magnetic field at its center is B. At what distance from the center, on the axis of the coil, the magnetic field will be B/8.
(a) \(\sqrt{2} \mathrm{R}\)
(b) 2R
(c) \(\sqrt{3} \mathrm{R}\)
(d) 3R
Answer:
(c) \(\sqrt{3} \mathrm{R}\)

Question 13.
Magnetic dipole moment is a vector quantity directed from:
(a) South to North Pole
(b) North to South Pole
(c) East to West direction
(d) West to East direction
Answer:
(a) South to North Pole

Question 14.
A wire of magnetic dipole moment M and L is bent into shape of a semicircle of radius r. What will be its new dipole moment?
\((a) \mathrm{M}
(b) \frac{M}{2 \pi}
(c) \frac{M}{\pi}
(d) \frac{2 M}{\pi}\)
Answer:
\((d) \frac{2 M}{\pi}\)

Question 15.
In a closed circuit of resistance 10W, the linked flux varies with time according to relation Φ = 6t² – 5t +1. At t = 0.25 second, the current (in Ampere) flowing through the circuit is :
(a) 0.4
(b) 0.2
(c) 2.0
(d) 4.0
Answer:
(b) 0.2

Question 16.
In A.C. circuit, the current and voltage are given by i = 5 cos wt, and V = 200 sin wt respectively. Power loss in the circuit is :
(a) 20 W
(b) 40W
(c) 1000W
(d) zero
Answer:
(d) zero

Question 17.
The energy of an electromagnetic radiation is 13.2 keV.
This radiation is related to which region of spectrum?
(a) Visible
(b) X-rays
(c) Ultra violet
(d) Infrared
Answer:
(b) X-rays

Question 18.
The image formed by objective lens of a compound Microscope is :
(a) Virtual and diminished
(b) Real and diminished
(c) Real and large
(d) Virtual and Large
Answer:
(c) Real and large

Question 19.
A convex lens is dipped in a liquid, whose refractive index is equal to refractive index of material of lens. Then its focal length will:
(a) become zero
(b) become infinite
(c) decrease
(d) increase
Answer:
(b) become infinite

Question 20.
Critical angle for light moving from medium I to medium II is 6. The speed of light in medium I is v. Then speed in medium II is :

Answer:
(b)

Question 21.
A magnifying glass is to be used at the fixed object distance of 1 inch. If it is to produce an erect image 5 items magnified, its focal length should be :
(a) 0.2″
(b) 0.8″
(c) 1.5″
(d) 5″
Answer:
(c) 1.5″

Question 22.
To remove hyper metropia lens used is :
(a) Convex
(b) Concave
(c) Cylindrical
(d) Plano-convex
Answer:
(a) Convex

Question 23.
Which of the following phenomena taken place when a monochromatic light is incident on a prism?
(a) Dispersion
(b) Deviation
(c) Interference
(d) All of the above
Answer:
(a) Dispersion

Question 24.
Optical fiber communication is based on which of the following phenomena:
(a) Total Internal reflection
(b) Scattering
(c) Reflection
(d) Interference
Answer:
(a) Total Internal reflection

Question 25.
The value of maximum amplitude produced due to interference of two waves is given by- y₁ = 4 sin wt and y₂ = 3 cos wt
(a) 7
(b) 5
(c) 1
(d) 25
Answer:
(b) 5

Question 26.
The phase difference 0 is related to Path difference Δx by:

Answer:
(c)

Question 27.
The resolving power of human eye (in minute) is :
(a) \(\frac{1}{60}\)
(b) 1
(c) 10
(d) \(\frac{1}{2}\)
Answer:
(a) \(\frac{1}{60}\)

Question 28.
A particle of mass m and charged q is accelerated through a potential V. The De-Broglie wavelength of the particle will be :

Answer:
(c)

Question 29.
The number of Photons of frequency 1014 Hz in radiation of 6.62J will be :
(a) 10¹⁰
(b) 10¹⁵
(c) 10²⁰
(d) 10²⁵
Answer:
(c) 10²⁰

Question 30.
The minimum angular momentum of electron in Hydrogen atom will be :
\((a) \frac{h}{\pi} J s
(b) \frac{h}{2 \pi} J s
(c) \mathrm{h} \pi \mathrm{Js}
(d) 2 \pi h J s\)
Answer:
\((b) \frac{h}{2 \pi} J s\)

Question 31.
The atomic number and mass number for a specimen are Z and A respectively. The number of neutrons in the atom will be :
(a) A
(b) Z
(c) A + Z
(d) A-Z
Answer:
(d) A-Z

Question 32.
The quantities, which remain conserved in a nuclear reaction:
(a) Total Charge
(b) Angular momentum
(c) Linear momentum
(d) All the above
Answer:
(d) All the above

Question 33.
Meaning of “FAX” is :
(a) Full Access Transmission
(b) Facsimile Telegraphy
(c) Factual Auto Access
(d) Feed Auto Exchange
Answer:
(b) Facsimile Telegraphy

Question 34.
A semiconductor is cooled from T₁K to T₂K, then its resistance will:
(a) increase
(b) decrease
(c) remain constant
(d) First decrease then increase
Answer:
(a) increase

Question 35.
If the current constant for a transistor are α & β then :
(a) αβ = l
(b) β > l, α < l
(c) α = β
(d) β < l, α > l
Answer:
(b) β > l, α < l

Bihar Board 12th Physics Objective Questions and Answers

Bihar Board 12th Physics Objective Answers Chapter 2 Electrostatic Potential and Capacitance

Question 1.
Which of the following statement is not true ?
(a) Electrostatic force is a conservative force.
(b) Potential at a point is the work done per unit charge in bringing a charge from infinity to that point.
(c) Electrostatic force is non-conservative.
(d) Potential is the product of charge and work.
Answer:
(b) Potential at a point is the work done per unit charge in bringing a charge from infinity to that point.

Question 2.
I volt is equivalent to

Answer:
\(\frac{\text { joule }}{\text { coulomb }}\)

Question 3.
The potential at a point due to a charge of 5 × 10^-7 C located 10 cm away is
(a) 3.5 × 10⁵ V
(b) 3.5 × 10⁴ V
(c) 4.5 × 10⁴ V
(d) 4.5 × 10⁵ V
Answer:
(c) 4.5 × 10⁴ V
Solution:
(c) Here, q = 5 × 10^-7C,r = 10cm = 0.1 m

Potential,

Question 4.
A charge +q is placed at the origin O of x-y axes as shown in the figure. The work done in taking a charge Q from A to B along the straight line AB is

Answer:
(a) \(\frac{\mathrm{qQ}}{4 \pi \varepsilon_{0}}\left(\frac{\mathrm{a}-\mathrm{b}}{\mathrm{ab}}\right)\)

Question 5.
The electric field and the potential of an electric dipole vary with distance r as

Answer:
(d) \(\frac{1}{r^{3}} \text { and } \frac{1}{r^{2}}\)

Question 6.
An electric dipole is placed at the centre of a hollow conducting sphere. Where of the following is correct ?
(a) Electric field is zero at every point of the sphere
(b) Electric field is not zero anywhere on the sphere
(c) The flux of electric field is not zero through the sphere
(d) All of these
Answer:
(b) Electric field is not zero anywhere on the sphere

Question 7.
The distance between H⁺ and Cl^– ions in HCl molecules is 1.38 Å. The potential due to this dipole at a distance of 10 Å on the axis of dipole is
(a) 2.1 V
(b) 1.8 V
(c) 0.2 V
(d) 1.2 V
Answer:
(c) 0.2 V

Question 8.
A cube of side x has a charge q at each of its vertices. The potential due to this charge array at the centre of the cube is

Answer:
(b) \(\frac{4 q}{\sqrt{3} \pi \varepsilon_{0} x}\)

Question 9.
A hexagon of side 8 cm has a charge 4 µC at each of its vertices. The potential at the centre of the hexagon is
(a) 2.7 × 10⁶ V
(b) 7.2 × 10¹¹ V
(c) 2.5 × 10¹² V
(d) 3.4 × 10⁴ V
Answer:
(a) 2.7 × 10⁶ V
Solution:
As shown in the figure, O is the centre of hexagon ABCDEF of each side 8 cm. As it is a regular hexagon OAB, OBC, etc are equilateral triangles,

∴OA = OB = OC = OD = OE = OF = 8 cm = 8 × 10^-2 m The potential at O is

Question 10.
Equipotential surfaces
(a) are closer in regions of large electric fields compared to regions of lower electric fields
(b) will be more crowded near sharp edges of a conductor
(c) will always be equally spaced
(d) both (a) and (b) are correct
Answer:
(d) both (a) and (b) are correct

Question 11.
What is the angle between electric field and equipotential surface ?
(a) 90° always
(b) 0° always
(c) 0°to90°
(d) 0° to 180°
Answer:
(a) 90° always

Question 12.
The work done to move a unit charge along an equipotential surface from P to Q
(a) must be defined as \(-\int_{\mathrm{P}}^{Q} \overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{d} \ell}\)
(b) is zero
(c) can have a non-zero value
(d) both (a) and (b) are correct
Answer:
(d) both (a) and (b) are correct

Question 13.
The work done in carrying a charge q once round a circle of radius a with a charge Q at its centre is

Answer:
(d) zero

Question 14.
A test charge is moved from lower potential point to a higher potential point. The potential energy of test charge will
(a) remains the same
(b) increase
(c) decrease
(d) becomes zero
Answer:
(c) decrease

Question 15.
Which among the following is an example of polar molecule ?
(a) O₂
(b) H₂
(c) N₂
(d) HCl
Answer:
(d) HCl

Question 16.
Dielectric constant for a metal is
(a) zero
(b) infinite
(c) 1
(d) 10
Answer:
(b) infinite

Question 17.
Metallic sphere of radius R is charged to potential V. Then charge q is proportional to
(a) V
(b) R
(c) both V and R
(d) none of these
Answer:
(c) both V and R

Question 18.
In a parallel plate capacitor, the capacity increases if
(a) area of the plate is decreased
(b) distance between the plates increases
(c) area of the plate is increased
(d) dielectric constant decreases.
Answer:
(c) area of the plate is increased

Question 19.
A parallel plate capacitor having area A and separated by distance d is filled by copper plate of thickness b. The new capacity is

Answer:
(c) \(\frac{\varepsilon_{0} A}{d-b}\)

Question 20.
Figure shows the Held lines of a positive point charge. The work done by the field in moving a small positive charge from Q to P is

(a) zero
(b) positive
(c) negative
(d) data insufficient
Answer:
(c) negative

Question 21.
The charge on 3 μF capacitor shown in the figure is

Answer:
(a) 2 μC
(b) 10 μC
(c) 6 μC
(d) 8 μC
Answer:
(b) 10 μC

Question 22.
Minimum number of capacitors each of 8 μF and 250 V used to make a composite capacitor of 16 μF and 1000 V are
(a) 8
(b) 32
(c) 16
(d) 24
Answer:
(b) 32
Solution:
(b) Minimum number of capacitors in each row

= \(\frac{1000}{250}=4\)
Therefore, 4 capacitors connected in series.
If there are m such rows, then total capacity = m x 2 = 16
∴ m = 16/2 = 8
∴ minimum number of capacitors = 4 x 8 = 32

Question 23.
A parallel plate capacitor is made by placing n equally spaced plates connected alternatively. If the capacitance between any two adjacent plates is C then the resultant capacitance is
(a) nC
(b) C/n
(c) (n + 1)C
(d) (n – 1)C
Answer:
(d) (n – 1)C

Question 24.
A parallel plate air capacitor has a capacitance C. When it is half filled with a dielectric of dielectric constant 5, the percentage increase in the capacitance will be
(a) 400%
(b) 66.6%
(c) 33.3%
(d) 200%
Answer:
(b) 66.6%

Question 25.
A capacitor of capacitance 700 pF is charged by 100 V battery. The electrostatic energy stored by the capacitor is
(a) 2.5 × 10^-8 J
(b) 3.5 × 10^-6 J
(c) 2.5 × 10^-4J
(d) 3.5 × 10^-4J
Answer:
(b) 3.5 × 10^-6 J
Solution:
(b) Here, C = 700 pF = 700 × 10^-12 F, V = 100 V

Energy stored

Question 26.
A 16 pF capacitor is connected to 70 V supply. The amount of electric energy stored in the capacitor is
(a) 4.5 × 10^-12 J
(b) 5.1 × 10^-8 J
(c) 2.5 × 10^-12 J
(d) 3.2 × 10^-8 J
Answer:
(b) 5.1 × 10^-8 J

Question 27.
A metallic sphere of radius 18 cm has been given a charge of 5 × 10^-6 C. The energy of the charged conductor is
(a) 0.2 J
(b) 0.6 J
(c) 1.2 J
(d) 2.4 J
Answer:
(b) 0.6 J
Solution:

Question 28.
Energy stored in a capacitor and dissipated during charging a capacitor bear a ratio
(a) 1 : 1
(b) 1 : 2
(c) 2 : 1
(d) 1 : 3
Answer:
(c) 2 : 1
Solution:
(c) Half of the energy is dissipated during charging a capacitor.

Question 29.
Van deGraaff generator is used to
(a) store electrical energy
(b) build up high voltages of few million volts
(c) decelerate charged particle like electrons
(d) both (a) and (b) are correct
Answer:
(b) build up high voltages of few million volts

Question 30.
Who established the fact of animal electricity ?
(a) Van deGraaff
(b) Count Alessandro Volta
(c) Gustav Robert Kirchhoff
(d) Hans Christian Oersted
Answer:
(b) Count Alessandro Volta

Question 31.
In case of a Van de Graaff generator, the breakdown field of air is
(a) 2 × 108 V m^-1
(b) 3 × 106 V m^-1
(c) 2 × 1CT8 V m^-1
(d) 3 × 104 V m^-1
Answer:
(b) 3 × 106 V m^-1

Question 32.
A capacitor of 4 μF is connected as shown in the circuit. The internal resistance of the battery is 0.5 Ω . The amount of charge on the capacitor plates will be

(a) 0
(b) 4 μC
(c) 16 μC
(d) 8 μC
Answer:
(d) 8 μC

Question 33.
Equipotentials at a great distance from a collection of charges whose total sum is not zero are approximately
(a) spheres
(b) planes
(c) paraboloids
(d) ellipsoids
Answer:
(a) spheres

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 4 Reproductive Health

Question 1.
RCH stands for
(a) routine check-up of health
(b) reproduction cum hygiene
(c) reversible contraceptive hazards
(d) reproductive and child health care.
Answer:
(d) reproductive and child health care.

Question 2.
Amminocentesis is a technique used to
(a) determine errors in amino acid metabolism in embryo
(b) pin point specific cardiac ailments in embryo
(c) determine any hereditary genetic abnormality in embryo
(d) all of these.
Answer:
(a) determine errors in amino acid metabolism in embryo

Question 3.
Which of the following cannot be detected in a developing foetus by amniocentesis ?
(a) Jaundice
(b) Down’s syndrome
(c) Cystic fibrosis
(d) Colourblindness
Answer:
(a) Jaundice

Question 4.
In which of the following weeks of pregnancy CVS is done ?
(a) 12th – 14th week
(b) 8th – 10th week
(c) 5th – 7th week
(d) None of these
Answer:
(b) 8th – 10th week

Question 5.
Causes for increased population growth in india is/are
(a) increase in birth rate
(b) decrease in death rate
(c) lack of education
(d) all of these.
Answer:
(d) all of these.

Question 6.
Which of the following pairs contributes to an increase in population ?
(a) Natality and immigration
(b) Mortality and emigration
(c) Natality and emigration
(d) Mortality and immigration
Answer:
(a) Natality and immigration

Question 7.
Which of the following is correct regarding the consequences of lower population ?
(a) It increases the poverty of a country.
(b) It leads to shortage of food supply.
(c) It results in unemployment
(d) All of these
Answer:
(d) All of these

Question 8.
The best way to decrease population of a country is
(a) to educate people
(b) to have better houses
(c) to kill people on a large scale
(d) to practice and implement familay planning.
Answer:
(d) to practice and implement familay planning.

Question 9.
Which of the following correctly describes the measures
that can be used to control over-population ?
(a) Educating people about the advantages of a small family
(b) Raising the age of marriage
(c) Encouraging family planning programme
(d) All of these
Answer:
(d) All of these

Question 10.
Which of the following is not a characteristic of an ideal contraceptive ?
(a) User-friendly
(b) Irreversible
(c) Easily available
(d) Least side-effects
Answer:
(b) Irreversible

Question 11.
On which of the following facts does the method of periodic abstinence is based ?
(a) Ovulation occurs on about the 14th day of menstruation.
(b) Ovum remains alive for about 1-2 days.
(c) Sperms survive for about 3 days.
(d) All of these
Answer:
(d) All of these

Question 12.
Which of the following is a non-medicated intrauterine device (IUD) ?
(a) CuT
(b) Lippes Loop
(c) Cu7
(d) LNG-20
Answer:
(b) Lippes Loop

Question 13.
Multiload device contains
(a) manganese
(b) iron
(c) copper
(d) calcium
Answer:
(c) copper

Question 14.
Which of the following is not an intrauterine device ?
(a) Progestasert
(b) Multiload-375
(c) Norplant
(d) Lippes loop
Answer:
(c) Norplant

Question 15.
What is the work of copper-T ?
(a) To inhibit ovulation
(b) To inhibit fertilisation
(c) To inhibit implantation of blastocyst
(d) To inhibit gametogenesis
Answer:
(b) To inhibit fertilisation

Question 16.
IUDs prevent pregnancy by
(a) inhibiting physiological and morphological uterine changes required for implantation.
(b) increasing phagocytosis of spermatozoa within uterus
(c) suppressing motility of sperms as well as their fertilising capacity
(d) all of these.
Answer:
(d) all of these.

Question 17.
Cu ions released from copper releasing intrauterine devices (IUDs)
(a) prevent ovulation
(b) make uterus unsuitable for implantation
(c) decrease phagocytosis of sperms
(d) suppress sperm motility.
Answer:
(d) suppress sperm motility.

Question 18.
The birth control device used by women is
(a) diaphragm
(b) vault
(c) copper T
(d) all of these.
Answer:
(d) all of these.

Question 19.
The most important component of oral contraceptive pills is
(a) progesterone-estrogen
(b) growth hormore
(c) thyroxine
(d) luteinising hormone.
Answer:
(a) progesterone-estrogen

Question 20.
Progesterone pill helps in preventing pregnancy by not allowing
(a) ova formation
(b) fertilisation
(c) implantation
(d) none of these.
Answer:
(a) ova formation

Question 21.
What is true about “Saheli” ?
(i) Developed at the CDRI, Lucknow
(ii) Contains a steroidal preparation
(iii) “Once-a-weak” pill
(iv) Many side effects
(v) High contraceptive value
(vi) Very few side effects value
(vii) Low contraceptive value
(a) (i), (ii), (iii), (v), (vi)
(b) (i), (iii), (v), (vi), (vii)
(c) (i), (ii), (iii), (iv), (v)
(d) (i), (iii), (iv), (v)
Answer:
(d) (i), (iii), (iv), (v)

Question 22.
What is the figure given below showing in particular ?

(a) Ovarian cancer
(b) Uterine cancer
(c) Tubectomy
(d) Vasectomy
Answer:
(c) Tubectomy

Question 23.
Which of the following birth control measures can be considered as the safest ?
(a) The rhythm method
(b) The use of physical barriers
(c) Termination of unwanted pregnancy
(d) Sterilisation techniques
Answer:
(d) Sterilisation techniques

Question 24.
Which of the following is the most widely accepted method of contraception in India at present ?
(a) Cervical caps
(b) Tubectomy
(c) Diaphragms
(d) IUDs (Intra uterine devices)
Answer:
(d) IUDs (Intra uterine devices)

Question 25.
Which of the following is a full proof method contraception ?
(a) Implantation
(b) Lactational amenorrhea
(c) Condoms
(d) Sterilisation
Answer:
(d) Sterilisation

Question 26.
Which of the following statements is correct regarding vasectomy ?
(a) It prevents the production of sperm in the testes.
(b) It prevents the production of semen.
(c) It prevents the movement of sperm into the urethra.
(d) It prevents a man from having an erection.
Answer:
(c) It prevents the movement of sperm into the urethra.

Question 27.
Which of the following statements is incorrect regarding the medical termination of pregnancy (MTP) ?
(a) These help in getting rid of unwanted pregnancies.
(b) These help in aborting the pregnancies which may be harmful to either mother of foetus or both.
(c) These contribute in decreasing the human population.
(d) None of these.
Answer:
(d) None of these.

Question 28.
Which of the following represents the correct match of a sexually transmitted disease with its pathogen ?
(a) Syphilis-Treponema pallidum
(b) Gonorrhoea-Entamoeba histolytica
(c) Urethritis-Bacillus anthracis
(d) Softsore-Bacillus brevis
Answer:
(a) Syphilis-Treponema pallidum

Question 29.
The sexually transmitted disease, that can affect both the male and the female genitals and may damage the eyes of babies born of infected mothers is
(a) AIDS
(b) syphilis
(c) gonorrhoea
(d) hepatitis
Answer:
(c) gonorrhoea

Question 30.
A sexually transmitted disease symptomised by the development of chancre on the genitals is caused by the infection of
(a) Treponema pallidum
(b) Neisseria gonorrhoeae
(c) human immunodeficiency virus
(d) hepatitis B virus
Answer:
(a) Treponema pallidum

Question 31.
Which of the following is correct regarding HIV, hepatitis B, gonorrhoea, trichomoniasis ?
(a) Trichomoniasis is an STD whereas others are not.
(b) Gonorrhoea is a viral disease whereas others are bacterial.
(c) HIV is a pathogen whereas others are diseases.
(d) Hepatitis B is eradicated completely whereas others are not.
Answer:
(c) HIV is a pathogen whereas others are diseases.

Question 32.
Which one of the following groups includes sexually transmitted diseases caused by bacteria only ?
(a) Syphilis, gonorrhoea, chancroid
(b) Syphilis, chlamydiasis, chancroid
(c) Syphilis, gonorrhoea, scabies
(d) Syphilis, scabies, pediculosis
Answer:
(a) Syphilis, gonorrhoea, chancroid

Question 33.
Confirmatory test for STDs is
(a) ELISA
(b) PCR
(c) DNA hybridisation
(d) all of these.
Answer:
(d) all of these.

Question 34.
Hepatitis B is transmitted through
(a) blood transfusion
(b) intimate physical contact
(c) sexual contact
(d) all of these
Answer:
(d) all of these

Question 35.
The common means of transmission of AIDS is
(a) sexual intercourse
(b) blood transfusion
(c) placental transfer
(d) all of these.
Answer:
(d) all of these.

Question 36.
Which of the following STDs are not completely curable ?
(a) Chlamydiasis, gonorrhoea, trichomoniasis
(b) Chancroid syphilis, genital warts
(c) AIDS, syphilis, hepatitis B
(d) AIDS, genital herpes, hepatitis B
Answer:
(d) AIDS, genital herpes, hepatitis B

Question 37.
World AIDS day is
(a) December 21
(b) December 1
(c) November 1
(d) June 11
Answer:
(b) December 1

Question 38.
In vitro fertilisation is a technique that involves transfer of which one of the following into the fallopian tube ?
(a) Embryo only, upto 8 cell stage
(b) Either zygote or early embryo upto 8 cell stage
(c) Embro of 32 cell stage
(d) Zygote only
Answer:
(b) Either zygote or early embryo upto 8 cell stage

Question 39.
The test-tube baby programme employs which one of the following techniques ?
(a) Zygote intra Fallopian transfer (ZIFT)
(b) Intra uterine insemination (IUI)
(c) Gamete intra Fallopian transfer
(d) All of these
Answer:
(a) Zygote intra Fallopian transfer (ZIFT)

Question 40.
The first case of IVF-ET technique success, was reported by
(a) Louis joy Brown and Banting Best
(b) Patrick Steptoe and Rebert Edwards
(c) Robert Steptoe and Gilbert Brown
(d) Baylis and Starling Taylor.
Answer:
(b) Patrick Steptoe and Rebert Edwards

Question 41.
Which of the following is ART ?
(a) IUDs
(b) GIFT
(c) ZIFT
(d) Both (b) & (c)
Answer:
(d) Both (b) & (c)

Question 42.
The technique called Gamete Intra Fallopian Transfer (GIFT) is recommended for those females
(a) who cannot produce an ovum
(b) who cannot retain the foetus inside uterus
(c) who cannot provide suitable environment for fertilisation
(d) all of these
Answer:
(a) who cannot produce an ovum

Question 43.
Which method can be used for women that cannot produce ovum but can provide suitable environment ?
(a) IUD
(b) GIFT
(c) IUI
(d) ICSI
Answer:
(b) GIFT

Question 44.
Which of these can be used to cure infertility in couples where male partner has very low sperm count ?
(a) IUD
(b) GIFT
(c) IUI
(d) None of these
Answer:
(c) IUI

Question 45.
The method of directly injecting a sperm into ovum in assisted reproductive technology is called
(a) GIFT
(b) ZIFT
(c) ICSI
(d) ET
Answer:
(c) ICSI

Question 46.
Increased IMR and decreased MMR in a population will
(a) cause rapid increase in growth rate
(b) result in decline in growth rate
(c) not cause significant change in growth rate
(d) result in an explosive population.
Answer:
(b) result in decline in growth rate

Question 47.
Intensely lactating mothers do not generally conceive due to the
(a) suppression of gonadotropins
(b) hypersecretion of gonadotropins .
(c) suppression of gametic transport
(d) suppression of fertilisation.
Answer:
(a) suppression of gonadotropins

Question 48.
A national level approach to build up a reproductively healthy society was taken up in our country in
(a) 1950s
(b) 1960s
(c) 1980s
(d) 1990s
Answer:
(a) 1950s

Question 49.
Emergency contraceptives are effective if used within,
(a) 72 hrs of coitus
(b) 72 hrs of ovulation
(c) 72 hrs of menstruation
(d) 72 hrs of implantation.
Answer:
(a) 72 hrs of coitus

Question 50.
From the sexually transmitted diseases mentioned below, identify the one which does not specifically affect the sex organs.
(a) Syphilis
(b) AIDS
(c) Gonorrhea
(d) Genital warts
Answer:
(b) AIDS

Question 51.
Condoms are one of the most popular contraceptives because of the following reasons.
(a) These are effective barriers for insemination.
(b) They do not interfere with coital act.
(c) These help in reducing the risk of STDs.
(d) All of the above
Answer:
(d) All of the above

Question 52.
The correct surgical procedure as a contraceptive method is
(a) ovariectomy
(b) hysterectomy
(c) vasectomy
(d) castration.
Answer:
(c) vasectomy

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 8 Human Health and Disease

Question 1.
Which of the following facrtors affect human health ?
(i) Infections
(ii) Silent mutation
(iii) Life style
(iv) Genetic disorders
(a) (i), (ii)and(iv)
(b) (i) and (ii)
(c) (i), (iii) and (iv)
(d) (i), (ii), (iii) and (iv)
Answer:
(c) (i), (iii) and (iv)

Question 2.
Which one of the following disease is non – communicable ?
(a) Diphtheria
(b) Flu
(c) Cancer
(d) Malaria
Answer:
(c) Cancer

Question 3.
Which of the following pairs contains an infectious and a non-infectious disease respectively ?
(a) Typhoid and AIDS
(b) AIDS and cancer
(c) Pneumonia and malaria
(d) Cancer and malaria
Answer:
(b) AIDS and cancer

Question 4.
Typhoid fever in human beings is caused by
(a) Plasmodium vivax
(b) Trichophyton
(c) Salmonella typhi
(d) Rhinoviruses.
Answer:
(c) Salmonella typhi

Question 5.
Which of the following is the bacterial disease in humans ?
(a) Dysentery
(b) Malaria
(c) Plague
(d) Both (a) & (c)
Answer:
(d) Both (a) & (c)

Question 6.
Which of the following pathogens causes whooping coough ?
(a) Legionella spp.
(b) Bordetella pertussis
(c) Vibrio cholerae
(d) Burcella melitensis
Answer:
(b) Bordetella pertussis

Question 7.
Which one of the following sets includes bacterial diseases ?
(a) Tetanus, tuberculosis, measles
(b) Diptheria, leprosy, plague
(c) Cholera, typhoid, mumps
(d) Malaria, mumps, poliomyelits
Answer:
(b) Diptheria, leprosy, plague

Question 8.
The common cold is caused by
(a) Rhino viruses
(b) Streptococcus pnemoniae
(c) Salmonella typhimurium
(d) Plasmodium vivax.
Answer:
(a) Rhino viruses

Question 9.
Hepatitis B is transmitted through
(a) sneezing
(b) female Anopheles
(c) coughing
(d) blood transfusion.
Answer:
(b) female Anopheles

Question 10.
A toxic substance, responsible for the chills and high fever recurring every three to four days in malarial fever, is
(a) interferon
(b) haemozoin
(c) hirudin
(d) colostrum
Answer:
(b) haemozoin

Question 11.
During the life cycle of Plasmodium, sexual reproduction takes place in which of the following hosts ?
(a) Human
(b) Female Anopheles mosquito
(c) Male Anopheles mosquito
(d) Both (a) and (b)
Answer:
(b) Female Anopheles mosquito

Question 12.
Amoebic dysentery (amoebiasis) is caused by
(a) Entamoeba histolytica
(b) E. coli
(c) Streptococcus pneumoniae
(d) Trichophyton.
Answer:
(a) Entamoeba histolytica

Question 13.
Which one of the following diseases cannot be cured by taking antibiotics ?
(a) Plague
(b) Amoebiasis
(c) Leprosy
(d) Whooping cough
Answer:
(b) Amoebiasis

Question 14.
An intestinal parasite which causes blockage of the intestinal passage and whose eggs are excreted along with the faeces of infected person is ______.
(a) Wuchereria bancrofti
(b) Ascaris
(c) Epidermophyton
(d) Microsporum
Answer:
(b) Ascaris

Question 15.
Elephantiasis, a chronic inflammation that results in gross deformities is caused by
(a) Ascaris
(b) E.coli
(c) Wuchereria
(d) Trichophyton
Answer:
(c) Wuchereria

Question 16.
Which of the following is affected by the infection of Wuchereria bancrofti ?
(a) Lymphatic vessels
(b) Respiratory system
(c) Nervous system
(d) Blood circulation
Answer:
(a) Lymphatic vessels

Question 17.
Which of the following diseases is transmitted by the bite of the female mosquito vector ?
(a) Filariasis
(b) Amoebiasis
(c) Typhoid
(d) Pneumonia
Answer:
(a) Filariasis

Question 18.
Which of the following pairs correctly matches a disease and a pathogen causing it ?
(a) Typhoid – Salmonella typhi
(b) Pneumonia – Haemophilus pneumoniae
(c) Malaria – Ascaris lumbricoides
(d) Ringworm – Entamoeba histolytica
Answer:
(a) Typhoid – Salmonella typhi

Question 19.
The pathogen Microsporum responsible for ringworm disease in humans belongs to the same kingdom as that of
(a) Taenia, a tapeworm
(b) Ascaris, a roundworm
(c) Rhizopus, a mould
(d) Wuchereria, a filarial worm,
Answer:
(c) Rhizopus, a mould

Question 20.
Appearance of dry, scaly lesions with itching on various parts of the body are the symptoms of _______.
(a) elephantiasis
(b) ringworm
(c) ascariasis
(d) amoebiasis
Answer:
(b) ringworm

Question 21.
Gambusia is a fish which is being introduced into the ponds in order to check the vector-borne diseases such as
(a) dengue
(b) malaria
(c) chikungunya
(d) all of these.
Answer:
(d) all of these.

Question 22.
Which one of the following pairs of diseases is viral as well as transmitted by mosquitoes ?
(a) Encephalitis and sleeping sickness
(b) Yellow fever and sleeping sickness
(c) Elephantiasis and dengue
(d) Yellow fever and dengue
Answer:
(d) Yellow fever and dengue

Question 23.
Which one of the following pairs is not correctly matched ?
(a) Dengue fever – Fiavi-ribo virus
(b) Syphilis – Trichu ris inch jura
(c) Plague – Yersinia pesris
(d) Filariasis – Wuchereria banchrofri
Answer:
(b) Syphilis – Trichu ris inch jura

Question 24.
The term ‘immunity’ refers to
(a) mutalism between host and parasite
(b) ability of the host to fight the disease-causing organism
(c) ability of the parasite to survive within a host
(d) a fatal disease.
Answer:
(b) ability of the host to fight the disease causing organism

Question 25.
A person has developed interferons in his body. He seems to carry an infection of
(a) tetanus
(b) malaria
(c) measles
(d) typhoid
Answer:
(c) measles

Question 26.
The first line of defence in the immune system is provided by
(a) skin and mucous membrane
(b) inflammatory response
(c) the complement system
(d) none of these.
Answer:
(a) skin and mucous membrane

Question 27.
Primary response produced due to first time encounter with a pathogen is of
(a) high intensity
(b) low intenisty
(c) intermediate intensity
(d) no intensity.
Answer:
(b) low intenisty

Question 28.
Which of the following components does not participate in innate immunity ?
(a) Neutrophils
(b) Macrophages
(c) B-lymphocytes
(d) Natural killer cells
Answer:
(c) B-lymphocytes

Question 29.
Antibodies are secreted by
(a) T-lymphocytes
(b) B-lymphocytes
(c) both (a) and (b)
(d) natural killer cell.
Answer:
(b) B-lymphocytes

Question 30.
The antigen binding site of an antibody is present at
(a) the constant region
(b) the C-terminal
(c) the variable region
(d) between constant and variable region.
Answer:
(c) the variable region

Question 31.
Humoral immunity is associated with
(a) T-cells
(b) B-cells
(c) macrophages
(d) both (a) and (b)
Answer:
(b) B-cells

Question 32.
The antibody which can cross placental barrier is.
(a) IgA
(b) JgE
(c) IgM
(d) IgG.
Answer:
(d) IgG.

Question 33.
The most abundant class of immunoglobulins (Igs) in the body is
(a) IgA
(b) IgG
(c) IgE
(d) IgM
Answer:
(b) IgG

Question 34.
A protein or polysaccharide molecule that stimulates antibody formation.
(a) antigen
(b) antibiotics
(c) exotoxin
(d) endotoxins.
Answer:
(a) antigen

Question 35.
Passive immunity can be conferred directly by
(a) vaccines
(b) antitoxins
(c) colostrum
(d) both (b) & (c)
Answer:
(d) both (b) & (c)

Question 36.
Which form of pathogen is used in vaccination ?
(a) Activated and strong pathogenic antigens
(b) Inactivated and weakened pathogenic antigens
(c) Hyperactive and strong pathogen
(d) Preformed antibodies
Answer:
(b) Inactivated and weakened pathogenic antigens

Question 37.
Injection of antitoxin in tetanus confers which type of immunisation ?
(a) Active immunisation
(b) Passive immunisation
(c) Auto-immunisation
(d) Humoral immunisation
Answer:
(b) Passive immunisation

Question 38.
The term ‘antitoxin’ refers to a preparation containing
(a) B-lymphoctyes and T-lymphocytes
(b) antibodies to the toxin
(c) weakend pathogen
(d) inactivated T-lymphocytes.
Answer:
(b) antibodies to the toxin

Question 39.
The injection given against the snake venom contains
(a) antigenic proteins
(b) preformed antibodies
(c) attenuated pathogen
(d) all of these.
Answer:
(b) preformed antibodies

Question 40.
Vaccine against polio viruses is an example of
(a) auto-immunisation
(b) passive immunisation
(c) active immunisation
(d) simple immunisation
Answer:
(c) active immunisation

Question 41.
Hepatitis B vaccine is produced from
(a) inactivated viruses
(b) yeast
(c) Haemophilus influenzae
(d) Salmonella typhimurium.
Answer:
(b) yeast

Question 42.
Use of vaccines and immunisation programmes have controlled which of the following infectious diseases ?
(a) Polio and tetanus
(b) Diphtheria and pheumonia
(c) Cancer and AIDS
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)

Question 43.
The most abundant antibody produced against allergens is
(a) IgE
(b) IgA
(c) IgG
(d) IgM.
Answer:
(a) IgE

Question 44.
Which of the following cells actively participate during allergy ?
(a) B-lymphocytes
(b) Liver cells
(c) Mast cells
(d) Red blood cells
Answer:
(c) Mast cells

Question 45.
The drugs used to quickly reduce the symptoms of allergy are
(a) ati-histamine and adrenaline
(b) histamine and thyroxine
(c) adrenaline and a-interferon
(d) all of these
Answer:
(a) ati-histamine and adrenaline

Question 46.
An auto-immune disease is
(a) SCID
(b) rheumatoid arthritis
(c) myasthenia gravis
(d) both (b) and (c).
Answer:
(d) both (b) and (c).

Question 47.
Which out of the following groups represent auto-immune disorders ?
(a) SCID and diphtheria
(b) Diabetes mellitus (type 1) and rheumatic fever
(c) AIDS and cholera
(d) Hepatitis and leukaemia
Answer:
(b) Diabetes mellitus (type 1) and rheumatic fever

Question 48.
The primary lymphoid organs are
(a) spleen and thymus
(b) bone marrow and thymus
(c) bone marrow and lymph node
(d) thymus and MALT.
Answer:
(d) thymus and MALT.

Question 49.
The site where lymphocytes interact with antigens and proliferate to become effector cells are
(a) spleen and lymph nodes
(b) bone marrow and thymus
(c) Peyer’s patches and tonsils
(d) both (a) and (c).
Answer:
(d) both (a) and (c).

Question 50.
Which of these glands is large at the time of birth but in adults, it reduces to a very small size ?
(a) Thyroid
(b) Adrenal
(c) Thymus
(d) Spleen
Answer:
(c) Thymus

Question 51.
MALT is
(a) Muscle Associated Lymphoid Tissues
(b) Mucosal Associated Lymphoid Tissues
(c) Mucosal and Lymphoid Tissue
(d) Memory Association Lymphoid Tissues.
Answer:
(b) Mucosal Associated Lymphoid Tissues

Question 52.
The lymphoid tissue, located within the lining of digestive tract is
(a) spleen
(b) Peyer’s pathes
(c) lymph nodes
(d) MALT
Answer:
(d) MALT

Question 53.
The abbreviation AIDS stands for
(a) Acquired immuno disease syndrome
(b) Acquired immuno deficiency syndrome
(c) Acquired immunity determining syndrome
(d) Acquired immunity delay syndrome.
Answer:
(b) Acquired immunodeficiency syndrome

Question 54.
The genetic material of HIV is
(a) dsDNA
(b) dsRNA
(c) ssDNA
(d) ssRNA
Answer:
(d) ssRNA

Question 55.
The human immunodeficiency virus is
(a) an unenveloped, RNA genome containing retrovirus
(b) an enveloped, RNA genome containing retrovirus
(c) an enveloped, DNA genome containing retrovirus
(d) an enveloped, RNA genome containing reovirus.
Answer:
(b) an enveloped, RNA genome containing retrovirus

Question 56.
Which of the following is not a cause of transmission of HIV?
(a) Multiple sexual partners
(b) Sharing infected needles
(c) Mosquito bite
(d) Transfusion of contaminated blood
Answer:
(c) Mosquito bite

Question 57.
Viral DNA after being converted from viral RNA by X, incorporates into host genome to undergo replication. What is‘X’ ?
(a) DNA polymerase
(b) Restriction endonuclease
(c) RNA polymerase
(d) Revers transcriptase
Answer:
(d) Revers transcriptase

Question 58.
The cells called ‘HIV factory’ is
(a) helper T-cells
(b) macrophages
(c) dendritic cells
(d) WBCs.
Answer:
(b) macrophages

Question 59.
HIV is a retrovirus that attacks
(a) helper T-cells
(b) cytotoxin t-cells
(c) B-cells
(d) neutrophils.
Answer:
(a) helper T-cells

Question 60.
AIDS is characterised by
(a) decrease in the number of killer T-cells
(b) decrease in the number of suppressor T-cells
(c) decrease in the number of helper T-cells
(d) increase in the number of helper T-cells
Answer:
(c) decrease in the number of helper T-cells

Question 61.
AIDS is widely diagnosed by
(a) Widal test
(b) ELISA
(c) PC
(d) Chromatography.
Answer:
(b) ELISA

Question 62.
Which of the following day is celebrated as ‘World AIDS Day’ ?
(a) 31st March
(b) 1st March
(c) Ist December
(d) 31st December
Answer:
(c) Ist December

Question 63.
Cancer cells do not exhibit the property of
(a) generating tumors
(b) metastasis
(c) contact inhibition
(d) less number of mitochondrial^cristae.
Answer:
(c) contact inhibition

Question 64.
A person suffering from leukaemia has
(a) tumors in adipose tissue
(b) increased number of plasma cells
(c) increased number of melanocytes
(d) increased number of WBCs.
Answer:
(d) increased number of WBCs.

Question 65.
A metastatic cancerous tumour is termed ‘sarcoma’ if the disorder is in
(a) fibroblasts
(b) circulatory system
(c) immune system
(d) epithelial cells.
Answer:
(a) fibroblasts

Question 66.
A chemical carcinogen present in tobacco smoke is responsible for
(a) skin cancer
(b) pancreatic cancer
(c) stomach cancer
(d) lung cancer.
Answer:
(d) lung cancer.

Question 67.
Major factors that cause cancer are
(a) oncogenes and polymorphonuclear leucocytes
(b) oncogenes and tumour suppressor genes
(c) MHC genes
(d) cellular oncogenes and a-interferons.
Answer:
(b) oncogenes and tumour suppressor genes

Question 68.
Which of the following approaches are used for the treatment of cancer ?
(a) Immunotherapy
(b) Surgery
(c) Radiotherapy & chemotherapy
(d) All of these
Answer:
(d) All of these

Question 69.
The substance given to cancer patients in order to activate their immune system and destroy the tumour is
(a) histamine
(b) interleukin
(c) a-interferon
(d) morphine.
Answer:
(c) a-interferon

Question 70.
In humans, receptors for opioids are present in
(a) central nervous system
(b) gastrointestinal tract
(c) respiratory tract
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

Question 71.
Heroin is commonly called as
(a) coke
(b) crack
(c) smack
(d) charas.
Answer:
(c) smack

Question 72.
Which compound is formed by acetylation of morphine ?
(a) Heroin
(b) Cocaine
(C) Tobacco.
(d) Marijuana
Answer:
(a) Heroin

Question 73.
Marijuana is extracted from .
(a) dried leaves and flowers of hemp plant .
(b) ergot fungus
(c) roots of hemp plant
(d) cocoa plant.
Answer:
(a) dried leaves and flowers of hemp plant .

Question 74.
Charas and ganja are the drugs which affect
(a) respiratory system
(b) cardiovascular system
(c) digestive system
(d) nervous system.
Answer:
(b) cardiovascular system

Question 75.
Cocaine is obtained from
(a) Erythroxylon coca
(b) Papaver somniferum
(c) Atropa belladona
(d) Dature stramonium
Answer:
(a) Erythroxylon coca

Question 76.
Cocaine is commonly called as
(a) smack
(b) coke
(c) crack
(d) both(b)&(c)
Answer:
(d) both(b)&(c)

Question 77.
_______ is a CNS stimulant as it interferes with the trasport of the neuro-transmitter __________ .
(a) Cocaine, acetylcoline
(b) Barbituarate, glutamate
(c) Cocaine, dopamine
(d) Barbiturate, glycine
Answer:
(c) Cocaine, dopamine

Question 78.
Whihc of the following plants possess hallucinogenic properties ?
(a) Erythroxylon coca
(b) Atropa belladona
(c) Datura stramonium
(d) All of these
Answer:
(d) All of these

Question 79.
Which drug is being excessively taken by some sports persons nowadays ?
(a) Opioids
(b) Barbiturates
(c) Cannabinoids
(d) Lysergic acid diethly amides (LSD)
Answer:
(c) Cannabinoids

Question 80.
Which drug is used as medicine to help patients cope with depression and insomnia ?
(a) Morphine
(b) Amphetamines
(c) Barbiturate
(d) Both (b) and (c)
Answer:
(d) Both (b) and (c)

Question 81.
Which one of the following is an opiate narcotic ?
(a) Barbiturates
(b) Morphine
(c) Amphetamines
(d) LSD
Answer:
(b) Morphine

Question 82.
Which one of the following is a mismatched pair of the drug and its effect ?
(a) Amphetamines – CNS stimulants
(b) Lysergic acid Diethlyamide (LSD) – Psychedelic (hallucinogen)
(c) Heroin – Depressant, slows down body functions
(d) Barbiturates – Transquilliser
Answer:
(d) Barbiturates – Transquilliser

Question 83.
The addictive chemical present in tobacco is
(a) caffeine
(b) nicotine
(c) catechol
(d) carbon monoxide.
Answer:
(b) nicotine

Question 84.
Level of which hormones get elevated by the intake of nicotine ?
(a) FSH,LH
(b) Thyroxine, progesterone
(c) Oxytocine, prolactin
(d) Adrenaline, nor-adrenaline
Answer:
(d) Adrenaline, nor-adrenaline

Question 85.
The intravenous drug abusers are more likely to develop
(a) cancer
(b) AIDS
(c) malaria
(d) typhoid.
Answer:
(b) AIDS

Question 86.
The organisms which cause diseases is plants and animals are called
(a) pathogens
(b) vectors
(c) insects
(d) worms.
Answer:
(a) pathogens

Question 87.
The chemical test that is used for diagnosis of tyhpoidis
(a) ELISA-Test
(b) EST-Test
(c) PCR-Test
(d) Widal-Test.
Answer:
(d) Widal-Test.

Question 88.
The sporozoites that cause infection, when a female Anopheles mosquito bites a person are formed in
(a) liver of the person
(b) RBCs of mosquito
(c) salivary glands of mosqiot
(d) intenstine of mosquito.
Answer:
(d) intenstine of mosquito.

Question 89.
The disease chikungunya is transmitted by
(a) house flies
(b) Aedes mosquitoes
(c) cockroach
(d) female Anopheles.
Answer:
(b) Aedes mosquitoes

Question 90.
The genes causing cancer are
(a) structural genes
(b) expressor genes
(c) oncogenes
(d) regulatory genes.
Answer:
(c) oncogenes

Question 91.
AIDS is caused by HIV. Among the following, which one is not a mode of transmission of HIV ?
(a) Transfusion of contaminated blood.
(b) Sharing the infected needles.
(c) Shaking hands with infected persons.
(d) Sexual contact with infected persons.
Answer:
(c) Shaking hands with infected persons.

Question 92.
‘Smack’ is a drug obtained from the
(a) latex of Papever somniferum
(b) leaves of Cannabis saliva
(c) flowers of Datura
(d) fruits of Erythroxyl coca.
Answer:
(a) latex of Papever somniferum

Question 93.
The substance produced by a cell in viral infection that can protect other cells from further infection is
(a) serotonin
(b) colostrum
(c) interferon
(d) histamine.
Answer:
(c) interferon

Question 94.
Antibodies present in colostrum which protect the new born from certain diseases is of
(a) IgG type
(b) IgA type
(c) IgD type
(d) IgE type.
Answer:
(b) IgA type

Question 95.
Tobacco consumption is known to stimulate secretion of adrenaline and nor-adrenaline. The component causing this could be
(a) nicotine
(b) tannic acid
(c) curaimin
(d) catechin.
Answer:
(a) nicotine

Question 96.
Antivenom against snake poison contains
(a) antigens
(b) antigen-antibody complexes
(c) antibodies
(d) enzymes
Answer:
(c) antibodies

Question 97.
Which of the following is not a lymphoid tissue ?
(a) Spleen
(b) Tonsils
(c) Pancreas
(d) Thymus
Answer:
(c) Pancreas

Question 98.
Which of the following glands is large sized at birth but reduces in size with ageing ?
(a) Pineal
(b) Pituitary
(c) Thymus
(d) Thyroid
Answer:
(c) Thymus

Question 99.
Haemozoin is a
(a) precursor of haemoglobin
(b) toxin released from Streptococcus infected cells
(c) toxin released from Plasmodium infected cells
(d) toxin released from Haemophilus infected cells.
Answer:
(c) toxin released from Plasmodium infected cells

Question 100.
One of the following is not the causal organism for ringworm.
(a) Microsporum
(b) Trichophyton
(c) Epidermophyton
(d) Macrosporum
Answer:
(d) Macrosporum

Question 101.
A person with sickle cell anaemia is
(a) more prone to malaria
(b) more prone to typhoid
(c) less prone to malaria
(d) less prone to typhoid.
Answer:
(c) less prone to malaria

Bihar Board 12th Biology Objective Questions and Answers

Bihar Board 12th Biology Objective Answers Chapter 7 Evolution

Question 1.
One of the possible early sources of energy was/were
(a) CO₂
(b) chlorophyll
(c) green plants
(d) UV rays and lightning.
Answer:
(d) UV rays and lightning.

Question 2.
Abiogenesis theory of origin supports
(a) spontaneous generation
(b) origin of life from blue-green algae
(c) origin of life is due to pre-existing organisms
(d) organic evolution is due to chemical reactions.
Answer:
(a) spontaneous generation

Question 3.
Who proposed that the first form of the could have come from pre-existing non-living organic molecules ?
(a) S.L. Miller
(b) Oparin and Haldane
(c) Charles Darwin
(d) Alfred Wallace
Answer:
(b) Oparin and Haldane

Question 4.
According to one of the most widely accepted theories, earth’s atmosphere before origin of life was
(a) oxidising
(b) oxidising along with H₂
(c) reducing with free O₂ in small amount
(d) reducing with oxygen absent in O₂ form.
Answer:
(b) oxidising along with H₂

Question 5.
According to Oparin, which one of the following was not present in the primitive atmosphere of the earth ?
(a) Methane
(b) Oxygen
(c) Hydrogen
(d) Water vapour
Answer:
(b) Oxygen

Question 6.
The correct sequence for the manufacture of the compounds on the primitive earth is
(a) NH_3, CH₄, protein and carbohydrate
(b) protein, carbohydrate, water and nucleic acid
(c) NH₃, CH₄, carbohydrate and nucleic acid
(d) NH₃, carbohydrate, protien and nucleic acid.
Answer:
(d) NH₃, carbohydrate, protien and nucleic acid.

Question 7.
Early at mosphere contained methane and other hydrocarbons. They have been now replaced by
(a) nitrogen
(b) oxygen
(c) carbon dioxide
(d) hydrogen.
Answer:
(c) carbon dioxide

Question 8.
The first life originated
(a) on land
(b) in air
(c) in water
(d) all of these.
Answer:
(c) in water

Question 9.
Coacervates are
(a) colloid droplets
(b) nucleoprotein containing entities
(c) microspheres
(d) both (a) and (b)
Answer:
(d) both (a) and (b)

Question 10.
First life from on earth was a
(a) cyanobacterium
(b) chemoheterotroph
(c) autotroph
(d) photoautotroph.
Answer:
(b) chemoheterotroph

Question 11.
The ship used by Charles Darwin during the sea voyages was
(a) HMS Beagle
(b) HSM Beagle
(c) HMS Eagle
(d) HSM Eagle.
Answer:
(a) HMS Beagle

Question 12.
Fitnes according to Darwin refers to
(a) number of species in a community
(b) useful variation in population
(c) strength of an individual
(d) reproductive fitness of an organism.
Answer:
(d) reproductive fitness of an organism.

Question 13.
Alfred Wallace worked in
(a) Galapagos Island
(b) Australian Island Continent
(c) Ma lay Archipelago
(d) none of these.
Answer:
(c) Ma lay Archipelago

Question 14.
The theory of natural selection was given by
(a) Lamarck
(b) Alfred Wallace
(c) Charles Darwin
(d) Oparin and Haldane.
Answer:
(c) Charles Darwin

Question 15.
The preserved fossil remains of Archaeopteryx show that
(a) it was a flying reptile from the Permian period
(b) reptiles gave rise to birds during Jurassic period
(c) it was a flying reptile in the Triassic period
(d) reptiles gave rise to birds during Permian period.
Answer:
(b) reptiles gave rise to birds during Jurassic period

Question 16.
Which of the following isotopes is used for Finding the fossil age maximum about 35,0000 years ?
(a) ²³⁸U
(b) ¹⁴C
(c) ³H
(d) ²⁰⁶Pb
Answer:
(b) ¹⁴C

Question 17.
Which of the following statements is True ?
(a) Wings to birds and insects are homologous organs.
(b) Human hands and bird’s wings are analogous organs.
(c) Human hands and bat’s wings are analogous organs.
(d) Flipper of penguin and dolphin are analogous organs.
Answer:
(d) Flipper of penguin and dolphin are analogous organs.

Question 18.
Replacement of the lighter-coloured variety of peppered moth (Biston betularia) to its darker variety (Biston carbonaria) in England is the example of
(a) natural selection
(b) regeneration
(c) genetic isolation
(d) temporal isolation.
Answer:
(a) natural selection

Question 19.
Phenomenon of ‘industrial melanism’ demonstrates
(a) geographical isolation
(b) reproductive isolation
(c) natural selection
(d) induced mutation.
Answer:
(c) natural selection

Question 20.
Which one of the following phenomena supports Darwin’s concept of natural selection in organic evolution ?
(a) Development of transgenic animals
(b) Production of “Dolly’, the sheep by cloning
(c) Prevalence of pesticide resistant insects
(d) Development of organs from ‘stem cells’ for organ transplantation.
Answer:
(c) Prevalence of pesticide resistant insects

Question 21.
The phenomenon ‘ontogeny repeats phylogeny’ is explained by
(a) recapitualtion theory
(b) Inheritcance theory
(c) mutation theory
(d) natural selection theory.
Answer:
(a) recapitualtion theory

Question 22.
The presence of gill slits, in the embryos of vertebrates, supports the theory of
(a) metamorphosis
(b) biogenesis
(c) organic evolution
(d) recapitulation
Answer:
(d) recapitulation

Question 23.
Which is not a vestigial organ in man ?
(a) Nictitating membrane
(b) Tail vertebrae
(c) Vermiform appendix
(d) Nails
Answer:
(d) Nails

Question 24.
Which one is not a vestigia organ ?
(a) Wings of kiwi
(b) Coccyx in man
(c) Pelvic girdle of python
(d) Flipper of seal
Answer:
(d) Flipper of seal

Question 25.
By the statement ‘survival of the fittest’, Darwin meant that
(a) the strongest of all species survives
(b) the most intelligent of the species survives
(c) the cleverest of the species survives
(d) the species most adaptable to changes survives.
Answer:
(d) the species most adaptable to changes survives.

Question 26.
Which of the following are the two key concepts of Darwinian theory of evolution ?
(a) Genetic drift and mutation
(b) Adaptive radiation and homology
(c) Mutation and natural selection
(d) Branching descent and natural selection
Answer:
(d) Branching descent and natural selection

Question 27.
According to Lamarckism, long necked giraffes evolved because
(a) nature selected only long necked ones
(b) humans preferred only long necked ones
(c) short necks suddenly changed into long necks
(d) of stretching of necks over many generations by short necked ones.
Answer:
(d) of stretching of necks over many generations by short necked ones.

Question 28.
Which of the following evidences does not favour the Lamarckian concept of inheritance of acquired characters ?
(a) Lack of pigment in cave-dwelling animlas
(b) Melanisation in peppered moth
(c) Absence of limbs in snakes
(d) Presence of webbed toes in aquatic birds
Answer:
(b) Melanisation in peppered moth

Question 29.
“Human population grows in geometric ratio while food materials increase in arithmetic proportion”. It is a statement from
(a) Darwin
(b) Bateson
(c) AmartyaSen
(d) Malthus.
Answer:
(d) Malthus.

Question 30.
Which one of the following scientist’s name is correctly matched with the theory put forth by him ?
(a) de Vries – Theory of natural selection
(b) Darwin – Theory of pangenesis
(c) Weismann – Theory of continuity of germplasm
(d) Pasteur – Theory of inheritance of acquired charcters
Answer:
(c) Weismann-Theory of continuity of germplasm

Question 31.
Single step large mutation leading to speciation is also called
(a) founder effect
(b) saltation
(c) branching descent
(d) natural selection
Answer:
(b) saltation

Question 32.
At a particular locus, frequency of allele A is 0.6 and that of allele a is 0.4. What would be the frequency of heterozygotes in a random mating population at equilibrium ?
(a) 0.36
(b) 0.16
(c) 0.24
(d) 0.48
Answer:
(d) 0.48

Question 33.
Hardy-Weinberg equilibrium is known to be affected by gene flow, genetic drift mutation, genetic recombination and
(a) evolution
(b) limiting facrtors
(c) saltation
(d) natural selection.
Answer:
(d) natural selection.

Question 34.
The Hardy-Weinberg principle cannot operate if
(a) a population does not migrate for a longtime to a new habitat.
(b) frequent mutations occur in the population
(c) the population has no chance of interaction with other populations
(d) free interbreeding occurs among all members of the population.
Answer:
(b) frequent mutations occur in the population

Question 35.
Genetic drift operates only in
(a) larger populations
(b) Mendelian populations
(c) island populations
(d) smaller populations.
Answer:
(d) smaller populations.

Question 36.
Which of the following is most important for speciation ?
(a) Seasonal isolation
(b) Reproductive isolation
(c) Behavioural isolation
(d) Tropical isolation
Answer:
(b) Reproductive isolation

Question 37.
The factors involved in the formation of new species are
(a) Isolation and competition
(b) gene flow and competition
(c) competition and mutation
(d) isolation and variation.
Answer:
(d) isolation and variation.

Question 38.
Stabilising selection favours
(a) both extreme forms of a trait
(b) intermediate forms of a trait
(c) environmental differences
(d) one extreme form over the other extreme form and over intermediate forms of a trait.
Answer:
(b) intermediate forms of a trait

Question 39.
The different forms of interbreeding species that live in different geographical regions are called
(a) sibling species
(b) sympatric species
(c) allopatric species
(d) polytypic species.
Answer:
(c) allopatric species

Question 40.
Which of following represents correct order of evolutiton ?
(a) Amoeba → Leucosolenia → Hydra → Ascaris
(b) Leucosolenia → Hydra → Amoeba → Ascaris
(c) Ascaris → Amoeba → Leucosolenia → Hydra
(d) None of these
Answer:
(a) Amoeba → Leucosolenia → Hydra → Ascaris

Question 41.
Presence of gills in the tadpole of frog indicated that
(a) fishes were amphibious in the past
(b) fishes evolved from frog-like ancestors
(c) frogs will have gills in future
(d) frogs evolved from gilled ancestors.
Answer:
(d) frogs evolved from gilled ancestors.

Question 42.
The character that proves that frogs have evolved from fishes is
(a) their ability to swim in water
(b) tadpole larva in frogs
(c) similarity in the shape of the head
(d) their feeding on aquatic plants.
Answer:
(b) tadpole larva in frogs

Question 43.
Identify the correct arrangement of periods of Palaeozoic era in ascending order in geological time scale.
(a) Cambrian → Devonian → Ordovician → Silurian → Carboniferous → Permian
(b) Cambrian → Ordovician → Silurian → Devonian→Carboniferous → Permian
(c) Cambrian → Ordovician → Devonian → Silurian → Carboniferous → Permian
(d) Silurian → Devonian → Cambrian → Ordovician → Permian → Carboniferous
Answer:
(b) Cambrian → Ordovician → Silurian → Devonian → Carboniferous → Permian

Question 44.
Which is the correct order of increasing geological time scale for a hypothetical vertebrate evolution ?
(a) Cenozoic, Mesozoic, Palaeozoic, Proterozoic
(b) Cenozoic, Palaeozoic, Mesozoic, Proterozoic
(c) Proterozoic, Cenozoic, Palaezoic, Mesozoic
(d) Proterozoic, Palaeozoic, Mesozoic, Cenozoic
Answer:
(d) Proterozoic, Palaeozoic, Mesozoic, Cenozoic

Question 45.
The ‘Devonian period’ is considered to be as
(a) age of fishes
(b) age of amphibians
(c) age of reptiles
(d) age of mammals.
Answer:
(a) age of fishes

Question 46.
Amphibians were dominant during _______ period.
(a) Carboniferous
(b) Silurian
(c) Ordovician
(d) Cambrian
Answer:
(a) Carboniferous

Question 47.
The primate which existed 15 mya was
(a) Homo habilis
(b) Australopithecus
(c) Ramapithecus
(d) Homo erectus
Answer:
(c) Ramapithecus

Question 48.
The extinct stone ancestor, who ate only fruits and hunted with stone weapons was
(a) Ramapithecus
(b) Australophecus
(c) Dryopithecus
(d) Homo erectus
Answer:
(b) Australophecus

Question 49.
One of the oldest, best preserved and most complete hominid fossil commonly known as ‘Lucy’ belongs to the genus
(a) Austraolopithecus
(b) Oreopithecus
(c) Dryopithecus
(d) Pithecanthropus
Answer:
(a) Austraolopithecus

Question 50.
The brain capacity of Homo eractus was about
(a) 650 c.c.
(b) 900 c.c.
(c) 1500 c.c.
(d) 1400 c.c.
Answer:
(b) 900 c.c.

Question 51.
The extinct human who lived 1,00,000 to 40,000 years ago, in East and Central Asia, used hides to protect their bodies and had brain capacity of 1400 c.c. were
(a) Homo habilis
(b) Neanderthal man
(c) Cro-Magnon man
(d) Ramapithecus.
Answer:
(b) Neanderthal man

Question 52.
Which of the following statements is correct ?
(a) Australopithecus has large brain around 900 c.c.
(b) Neanderthal man lived in East Africa and the fruits.
(c) Homo erectus had brain capacity 900 c.c.
(d) Homo sapiens arose in Central Asia and moved to other continuents and developed into distinct races.
Answer:
(c) Homo erectus had brain capacity 900 c.c.

Question 53.
Which of the following statements js correct regarding evolution of mankind ?
(a) Homo erectus is preceded by Homo habilis.
(b) Neanderthal man and Cro-Magnon man were living at the same time.
(c) Australopithecus was living in Australia.
(d) None of these
Answer:
(a) Homo erectus is preceded by Homo habilis.

Question 54.
The cranial capacity was largest among the
(a) Peking man
(b) Java ape man
(c) African man
(d) Neanderthal man.
Answer:
(d) Neanderthal man.

Question 55.
The most apparent change during the evolutionary history oiHomo sapiens is traced in
(a) loss of body hair
(b) walking unright
(c) sortening of the jaws
(d) remarkable, increase in the brain size.
Answer:
(d) remarkable, increase in the brain size.

Question 56.
What kind of evidences suggested that man is more closely related with chimpanzee than with other hominoid apes ?
(a) Evidence from DNA of sex chromosomes only
(b) Comparison of chromosome morphology and number
(c) Evidence from fossil remains, and the fossil mitochondrial DNA alone
(d) Evidence from banding pattern of chromosome 3 and 6
Answer:
(d) Evidence from banding pattern of chromosome 3 and 6

Question 57.
Which of the following eras, in geological time scale, corresponds to the period when life had not orginated upon the earth ?
(a) Azoic
(b) Palaeozoic
(c) Mesozoic
(d) Archaeozoic
Answer:
(a) Azoic

Question 58.
Homo sapiens arose during which epoch ?
(a) Pleistocene
(b) Pliocene
(c) Oligocene
(d) Holocene
Answer:
(d) Holocene

Question 59.
Study the human evolution is called
(a) archaeology
(b) anthropology
(c) pedigree analysis
(d) chronobiology.
Answer:
(b) anthropology

Question 60.
Which of the following is used as an atmospheric pollution indicator ?
(a) Lepidoptera
(b) Lichens
(c) Lycopersicon
(d) Lycopodium
Answer:
(b) Lichens

Question 61.
The theory of spontaneous generation stated that
(a) life arose from living forms only
(b) life can arise from both living and non-living
(c) life can arise from non-living things only
(d) life arises spontaneusly, neither from living nor from the non-living.
Answer:
(c) life can arise from non-living things only

Question 62.
Animal husbandry and plant breeding programmes are the examples of
(a) reverse evolution
(b) aritifical selection
(c) mutation
(d) natural selection.
Answer:
(d) natural selection.

Question 63.
Palaentological evidences for evolutaion refer to the
(a) development of embryo
(b) homologous organs
(c) fossils
(d) analogous organs.
Answer:
(c) fossils

Question 64.
The bones of forelimbs of whale, bat, cheeah and man are similar in structure, because
(a) one organism has given rise to another
(b) they share a common ancestor
(c) they perform the same function.
(d) the have biochemical similarities.
Answer:
(b) they share a common ancestor

Question 65.
Analogous organs arise due to
(a) divergent evolution
(b) artificial selection
(c) genetic drift
(d) convergent evolution.
Answer:
(d) convergent evolution.

Question 66.
(p+q)² = p² + 2pq + q² = 1 represents an equation used in
(a) population genetics
(b) Mendilian genetics
(c) biometircs
(d) molecular genetics.
Answer:
(a) population genetics

Question 67.
Appearnace of antibiotic-resistant bacteria is an example of
(a) adaptive radiation
(b) transduction
(c) pre-existing variation in the population
(d) divergent evolution.
Answer:
(c) pre-existing variation in the population

Question 68.
Fossils are generally found in
(a) sedimentasry rocks
(b) igneous rocks
(c) metamorphic rocks
(d) any type of rock.
Answer:
(a) sedimentasry rocks

Question 69.
Which type of selection is industrial melanism observed in moth, Biston betularia?
(a) Stabilising
(b) Directional
(c) Disruptive
(d) Artificial
Answer:
(b) Directional

Question 70.
Which of the following is an example for link species ?
(a) Lobe fish
(b) Dodo bird
(c) Seaweed
(d) Chimpanzee
Answer:
(a) Lobe fish

Question 71.
Variations during mutations of meiotic recombinations are
(a) random and directionless
(b) random and directional
(c) random and small
(d) random small and directional
Answer:
(a) random and directionless

Bihar Board 12th Chemistry Model Papers

Bihar Board 12th Chemistry Model Question Paper 4 in English Medium

Time : 3 Hours 15 Min
Full Marks: 70

Instructions for the candidates

1. Candidates are required to give answers in their own words as far as practicable.
2. Figures in the right hand margin indicates full marks.
3. While answering the questions, candidate should adhere to the words limit as far as practicable.
4. 15 Minutes of extra time has been allotted for the candidates to read the questions carefully.
5. This question paper is divided into two sections : Section -A and Section-B
6. In Section A, there are 35 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with blue/black ball pen against the correct option on OMR Sheet provided to you. Do not use Whitener/Liquid/Blade/ Nail on OMR Sheet otherwise your result will be treated as invalid.
7. In section-B, there are 18 short answer type questions (each carrying 2 marks), out of which only 10 (ten) questions are to be answered Apart from this there are 06 Long Answer type questions (each carrying 5 marks), out of which 3 questions are to be answered.
8. Use of any electronic device is prohibited.

Objective Type Questions

In the following questions no. from 1 to 35, there is only one correct answer against each question. For each question, mark (darken) the correct answer on the OMR Sheet provided to you. (1 x 35 = 35)

Question 1.
Which type of crystals contains more than one Bravais lattice ?
(a) Hexagonal
(b) Triclinic
(c) Rhombohedral
(d) Monoclinic
Answer:
(d) Monoclinic

Question 2.
For the structure given below the site marked as S is a …………….

(a) tetrahedral void
(b) cubic void
(c) octahedral void
(d) none of these
Answer:
(c) octahedral void

Question 3.
If the radius of an octahedral void is r and radius of atoms in close packing is R, the relation between r and R is
(a) r = 0.414 R
(b) R = 0.414 r
(c) r = 2R
(d) r = \(\sqrt{2} R\)
Answer:
(a) r = 0.414 R

Question 4.
A metal crystallises into a lattice containing a sequence of layers as AB AB AB………………… What percentage of voids are left in the lattice ?
(a) 72%
(b) 48%
(c) 26%
(d) 32%
Answer:
(c) 26%

Question 5.
In ccp arrangement the pattern of successive layers can be designated as
(a) AB AB AB
(b) ABC ABC ABC
(c) AB ABC AB
(d) ABA ABA ABA
Answer:
(b) ABC ABC ABC

Question 6.
A solution is obtained by mixing 200 g of 30% and 300 g of 20% solution by weight. What is the percentage of solute in the final solution ?
(a) 50%
(b) 28%
(c) 64%
(d) 24%
Answer:
(d) 24%

Question 7.
When 1.04 g of BaCl₂ is present in 10⁵ g of solution the concentration of solution is ………….
(a) 104 ppm
(b) 10.4 ppm
(c) 0104 ppm
(d) 104 ppm
Answer:
(b) 10.4 ppm

Question 8.
In the cell, |Zn²⁺| |Cu²⁺|Cu, the negative terminals
(a) Cu
(b)Cu²⁺
(c) Zn
(d) Zn²⁺
Answer:
(d) Zn²⁺

Question 9.
What will be standard cell potential of galvanic cell with the following reaction ?

(a) 74 V
(b) 1.14 V
(c) 34 V
(d) – 0.34 V
Answer:
(c) 34 V                         .

Question 10.
In a reaction 2HI → H₂ + I₂ the concentration of HI decreases from 0.5 mol L^-1 in 10 minutes. What is the rate of reaction during this interval ?
(a) 5 x 10^-3 M min^-1
(b) 5 x 10^-3 M min^-1
(c) 5 x 10^-2 M min^-1
(d) 5 x 10^-2 M min^-1
Answer:
(a) 5 x 10^-3 M min^-1

Question 11.
The rate of disappearance of SO, in the reaction, 2SO₂ + O₂  → 2SO₃ is 1.28 x 10^-5 Ms . The rate of appearance of SO₃ is ……………….
(a) 64 x 10^-5 M s^-1
(b) 0.32 x 10^-5 M s^-1
(c) 56 x 10^-5 Ms¹
(d) 1.28 x 10^-5  M s^-1
Answer:
(d) 1.28 x 10^-5  M s^-1

Question 12.
Which of the following is a property of physisorption ?
(a) High specificity
(b) Irreversibility
(c) Non-specificity
(d) None of these
Answer:
(c) Non-specificity

Question 13.
Which of the following statement is not correct about physisorption ?
(a) It is a reversible process
(b) It requires less heat of adsorption
(c) It requires activation energy
(d) It takes place at low temperature
Answer:
(c) It requires activation energy

Question 14.
The name of the metal which is extracted from the ore is given below. Mark the example which is not correct.
(a) Malachite – Cu
(b) Calamine – Zn
(c) Chromite – Cr
(d) Dolomite – Al
Answer:
(d) Dolomite – Al

Question 15.
Which of the followings is magnetite ?
(a) Fe₂CO₃
(b) Fe₂O₃
(c) Fe₃O₄
(d) Fe₂O₃.3H₂O
Answer:
(c) Fe₃O₄

Question 16.
Nitrogen can form only one chloride with chlorine which is NCl₃ whereas P can form PCl₃ and PCl₅. This is ……………
(a) due to absence of d-orbitals in nitrogen
(b) due to difference in size of N and P
(c) due to higher reactivity of P towards Cl than N
(d) due to presence of multiple bonding in nitrogen
Answer:
(a) due to absence of d-orbitals in nitrogen

Question 17.
On heating a mixture of NH₄Cl and KNO₂, we get
(a) NH₄NO₃
(b) KNH₄(NO₃)₂
(c) N₂
(d) NO
Answer:
(c) N₂

Question 18.
The melting point of copper is higher than that of zinc because
(a) the s, p as well as d-electrons of copper are involved in metallic bonding
(b) the atomic volume of copper is higher
(c) the d-electrons of copper are involved in metallic bonding
(d) the s as well as d-electrons of copper are involved in metallic bonding
Answer:
(c) the d-electrons of copper are involved in metallic bonding

Question 19.
Zr and Hf have almost equal atomic and ionic radii because of ………………….
(a) diagonal relationship
(b) lanthanoid contraction
(c) actinoid contraction
(d) belonging to the same group
Answer:
(b) lanthanoid contraction

Question 20.
Which of the following primary and secondary valencies are not correctly marked against the compounds ?
(a) [Cr(NH₃)₆]Cl₃, p = 3,s = 6
(b) K₂[Pt(CI₄],p = 2,s = 4
(c) [Pt(NH₃)₂Cl₂],p = 2,s = 4
(d) [Cu(NH₃)₄]SO₄,p = 4,s = 4
Answer:
(d) [Cu(NH₃)₄]SO₄,p = 4,s = 4

Question 21.
When aqueous solution of potassium fluoride is added to the blue coloured aqueous CuSO₄ solution, a green precipitate is formed. This observation can be explained as follows.
(a) On adding KF, H₂O being weak field ligand is replaced by F^– ions forming [CuF₄ ]^2- which is green in colour
(b) Potassium is coordinated to [Cu(H₂O)₄]²⁺ ion present in CuSO₄ and gives green colour
(c) On adding KF, Cu²⁺ are replaced by K⁺ forming a green complex
(d) Blue colour of CuSO₄ and yellow colour of KI form green colour on mixingAnswer:
(a) On adding KF, H₂O being weak field ligand is replaced by F^– ions forming [CuF₄ ]^2- which is green in colour

Question 22.
IUPAC name of CH₃)₂ CH — CH₂ — CH₂Br is
(a) 1-bromopentane
(b) 1-bromo-3-methylbutane
(c) 2-methyl-4-bromobutane
(d) 2-methyl-3-bromopropane
Answer:
(b) 1-bromo-3-methylbutane

Question 23.
The IUPAC name of the compound is

(a) 1 -fluoro-4-methyl-2-nitrobenzene
(b) 4-fIu6ro-lmethyl-3-nitrobenzene
(c) 4-methyl-l-fIuoro-2-nitrobenzene
(d) 2-fIuoro-5-methyl-l-nitrobenzene
Answer:
(d) 2-fIuoro-5-methyl-l-nitrobenzene

Question 24.
The C— O — H angle in ether is about
(a) 180°
(b) 190°28′
(c) 110°
(d) 105°
Answer:
(c) 110°

Question 25.
The C— O — H bond angle in alcohols is slightly less than the tetrahedral angle whereas the C— O — C bond angle in ether is slightly greater because ………
(a) of repulsion between the two bulky R groups.
(b) O atom in both alcohols and ethers is sp³-hybridised
(c) lone pair-lone pair repulsion is greater than bond pair­bond pair repulsion
(d) none of these
Answer:
(a) of repulsion between the two bulky R groups.

Question 26.
Propanone can be prepared from ethyne by
(a) passing a mixture of ethyne and steam over a catalyst, magnesium at 420°C
(b) passing a mixture of ethyne and ethanol over a catalyst zinc chromite
(c) boiling ethyne with water and H₂SO₄
(d) treating ethyne with iodine and NaOH
Answer:
(a) passing a mixture of ethyne and steam over a catalyst, magnesium at 420°C

Question 27.
In the following reaction, product (P) is

(a) RCHO
(b) RCH₃
(c) RCOOH
(d) RCH₂OH
Answer:
(a) RCHO

Question 28.
IUPAC name of the compound (C₂H₅)₂ NCH is
(a) 2, 2-diethylmethanamine
(b) N, N-diethylmethanamine
(c) N-ethyl-N-methylethanamine
(d) N-methylbutanamine
Answer:
(c) N-ethyl-N-methylethanamine

Question 29.
Reduction of aromatic nitro compounds using Sn and HCI gives
(a) armatic primary amines
(b) aromatic secondary amines
(c) aromatic tertiary amines
(d) aromatic amides
Answer:
(a) armatic primary amines

Question 30.
Which of the fol lowing is an example of an aldopentose ?
(a) D-Ribose
(b) Glyceraldehyde
(c) Fructose
(d) Erythrose
Answer:
(a) D-Ribose

Question 31.
Which of the following treatment will convert starch directly into glucose ?
(a) Heating with dilute H₂SO₄
(b) Fermentation by diastase
(c) Fermentation by zymase
(d) Heating with dilute NaOH
Answer:
(a) Heating with dilute H₂SO₄

Question 32.
The correct structure of monomers of buna-S is

Answer:
(c)

Question 33.
The S in buna-S refers to
(a) sulphur
(b) styrene
(c) sodium
(d) salicylate
Answer:
(b) styrene

Question 34.
The main cause of acidity in the stomach is
(a) release of extra gastric acid which decrease the pH level
(b) indidestion and pain in large intestine
(c) increase the pH level in the stomach
(d) release of extra bile juice which increase alkaline medium in stomach.
Answer:
(a) release of extra gastric acid which decrease the pH level

Question 35.
Which of the following will not act as antacid ?
(a) Sodium hydrogen carbonate
(b) Magnesium hydroxide
(c) Sodium carbonate
(d) Aluminium carbonate
Answer:
(c) Sodium carbonate

Non-Objective Type Questions

Short Answer Type Questions

In this Section, there are 18 Short answer type questions (each carrying 2 marks), out of which answer any 10 questions.  2 x 10 = 20

Question 1.
Calculate the osmotic pressure of 5% solution of urea at 272 K . (R = 0.0821 L-atm. deg^-1).
Answer:
As we know that \(\pi=\frac{n_{\text {urea }} R T}{V}\)
Number of moles in urea \(=\frac{5}{60}=0.083\)
Volume of Solution \(=\frac{100}{1000}=0.1\) litres
Hence, Osmotic Pressure, \(\pi=\frac{0.083 \times 0.0821 \times 272}{0.1}=18.53 \mathrm{atm}\)
Osmotic Pressure = 18.53atm

Question 2.
Define standard electrode potential.
Answer:
Standard Electrode Potential : The standard electrode potential is the potential difference between the electrode & electrolyte (at 1 M), at standard conditions (1 atm, 298 K). Standard electrode potential is abbreviated by (E or E°).

Question 3.
What is activation energy ? How is the rate constant of a reaction related to its activation energy ?
Answer:
Activation Energy: The minimum extra amount of energy absorbed by the reactant molecules so that their energy becomes equal to threshold value is called activation energy.
Activation energy (E_a)= Threshold energy (E_T) – Average energy of the reactant (E_R). i.e. E_a = E_T – E_R
If activation energy will be less, then faster will be the reaction.
i. e . Activation energy = \(\alpha \frac{1}{\text { rate of reaction }}\)
e.g. 2NO + O₂ → 2NO₂
It is a fast reaction because of low activation energy. 2CO + O₂ → 2CO₂
It is a slow reaction because of high activation energy.

Question 4.
What is the main difference between physiorption and Chemisorption ?
Answer:
Physisorption:

• Force of attraction are Vander Waal’s forces.
• It usually takes place at low temperature and decreases with increasing temperature.
• It does not require any activation energy.

Chemisorption :

• Force of attraction are chemical bond forces.
• It takes place at high temperature.
• It requires high activation energy.

Question 5.
Differentiate the following giving suitable example:
(i) Calcination and Roasting
(ii) Flux and Slag.
Answer:
(i) Calcination :
(a) Calcination is a thermal treatment process in absence of air applied to ores and materials to bring about a thermal decomposition, phase transition or removal of volalatile fraction It is done at temperature below the melting point of the product material.
(b)

Roasting:
(a) Roasting is reverse process of calcination. It is also thermal process in presence of air applied to ore for removal of volatile fraction under melting point of the product material is called Roasting.
(b)

Flux :
(a) It is chemical cleaning agent, which remove impurities from metal.
(b) Example – CaO + SiO₂ → CaSiO₃

Slag :
(a) Slag is partially vitereous by product of the process of smelting ores, which separates the desiredmetal fraction from the unwanted fraction. It is mixture of metal oxide
(b) Example – CaO + SiO₂ → CaSiO₃

Question 6.
Why do transition elements form coloured compounds ? Explain.
Answer:
The value of electrods potential depends upon the heat of sublimation and ionisation energy
ΔH – ΔH_sub + IE + ΔH_hyd . Due to the influence of ligand d-orbitals of transition metals divide into two unequal energy containing sets. Unpaired electrons absorb sunlight and jumps from one orbit into another orbit and one clour is reflected.

Question 7.
Predict the geometrical shapes of the following:
(a) sp³
(b)d²sp³
Answer:
(a) sp³ tetra-hedral
(b)d²SP³ – Square tetrahedral.

Question 8.
Specify oxidation numbers of the metals in the following co-ordination compounds:
(a) K₄[Fe(CN)₆]
(b) [PtCl₄]^2-
Answer:
(a) Oxidation number of (co-ordination compound)
Let oxidation number of Fe = x
Hence, 1 x 3 + (x -1 x 6 = 0
or, x – 3 = 0
x = 3 = O. N of Fe

(b) Oxidation number of (co-oridnation compaund)
Hence, x + 4 (-1) = – 2
or, x = -2 + 4 = + 2 = ON of Pt

Question 9.
Write the structural formulae of the following:
(a) 4,4 dimethyl-2-pentanol
(b) 2-butanol.
Answer:
(a) 4, 4 dimethyl, 2-Pentanol

Question 10.

Answer:

Question 11.
How will you convert the following ?
(a) Ethyl alcohol to ethylamine
(b) Ethylamine to ethyl alcohol.
Answer:

Question 12.
Explain in which of the following compounds, the chemical bond would have less ionic character: LiCl or KCl.
Answer:
LiCl > KCl – Due to large size of k, KCl compound has less ionic character. LiCl is covalent than Li⁺ has higher polarisation capacity.

Question 13.
Discuss briefly the structure of CsCl.
Answer:
Structure of CsCl.

Question 14.
The osmotic pressure of sugar solution is 2.46 atm at 27°C. Calculate the concentration of the solution.
Answer:

Question 15.
How is molarity of a solution different from molality?
Answer:
Molarity : It is defined as the number of moles of solute dissolved in one liter of solution
\(Molarity (\mathrm{M})=\frac{\text { Moles of solute }}{\text { Volume of Solution in liter }} \)

Molality : It is defined as the number of moles of solute dissolved in one kg of solvent
\(Molality (\mathrm{m})=\frac{\text { Moles of the Solute }}{\text { Mass of the solvent in } \mathrm{kg}}\)

Question 16.
Define heat of neutralisation.
Answer:
Defination of heat of neutralization : The heat reaction resulting from the neutralization of an acid or base especially the quantity produced when a gram equivalent of a base or acid is neutralized with a gram equivalent of an acid or base in dilute soliution.

Question 17.
(a) State law of mass action.
(b) What is the effect of temperature on reaction ?
Answer:
(a) Law of mass action: Law stating that the rate of any chemical reaction is proportional to the product of the masses of the reacting substances, with each mass raised to a power equal to the coefficient that occurs in the chemical equation.

(b) The effect of increasing collision frequency on the rate of the reaction is very minor increasing the temperature increases reaction rates because of the disproportionately large increase in the number of high energy collisions.

Question 18.
Discuss the following terms :
(a) Coordination number
(b) Effective atomic number.
Answer:
(a) The coordination number of a central atom in a molecure or crystal is the number of its near neighbours. This number is determined some what differently for molecules than for crystals.

(b) Effective atomic number has two different meaning; one that is the effective nuclear charge of an atom, and other that calculates the average atomic number for a compound or mixture of materials.

Long Answer Type Questions

There are 06 long answer type questions (each carrying 05 marks), out of which answer any there questions.
(5 x 3 = 15)

Question 19.
Define order to reaction and molecularity of relation. Derive a general expression for specific rate constant of first order reaction.
Answer:
It is the numbers of atom, ion, and molecule that collide with one another simultaneously so as to result into a chemical reaction
Rate constant → It is the speed at which the reactions are converted into the products at any moment of time.
Law of Mass Action → At a given temperature, the rate of a chemical reaction is directly proportional to the product of molar concentrations of reacting species with each concentration term raised to the power equal to numerical co-efficient of that species in the chemical reaction.
Thus, A + B → Products
Rate of reaction, r x [A] [B] = K [A] [B]
Where, [A] and [B] are the molar concentrations of the reactants A and B respectively and K is a constant of proportionality.
∴Rate = K [A]^a [B]^b

First Order Reaction – It is the type of reaction in which the rate of reaction depends only on the first power of the concentration of a single reacting Species.
Let, A + B → Product
If, a be the initial concentration of A and after time t, the concentration of product is x, then the concentration of A left at that instant is (a – x)
A → Products
initial conc._n (a)  ….(i)
after time ‘t’ (a – x)  … (ii)

Where, C → integration constant, which can be obtained from initial condition of the reaction, when, t = 0, x = 0,
then, from (iii) In (a – 0) = K x 0 + C
or, C = In (a)  ………….. (iv)
from (iii) + (iv) – In (a -x) = Kt – In (a)
or, In (a) – In (a – x) = kt or, In (a) – In (a – x) = kt.

Question 20.
(a) Differentiate between DNA and RNA.
(b) What are Nucleic acids ?
Answer:
(a) The structural difference between DNA and RNA
DNA : DNA is double stranded helix in which two strands are coiled spirally in opposite directions.

• The sugar molecule is 2-dehydrobase.
• Nitrogeneous base uracil is not present.
• DNA molecule are very large their molecules weights may vary from 6 million to 16.
• DNA has unique property of replication.

RNA :

• It is single strainded structure.
• The sugar molecules is ribose.
• Nitrogeneous base they-mine is not present.
• RNA molecules are much smaller with molecular weight ranging from 20000 to 40000.
• RNA usually doesn’t replicate.

(b) Nucleic acid – Nucleic acid are found in all living cells in form of nucleo proteins. They constitute important class of biomolecules. Nucleic acids are genetic material of the cells and are responsible for transmission of herediatry effect from one generation to the other and also carry out the biosynthesis of proteins. Nucleic acid are biopolymers (i.e., polymers present in living system). The genetic information about in nucleic acid controls the structure of all proteins including enzymes and thus governs the entire metabolic activity in the living organism.

Question 21.
(a) Discuss the principle involved in the manufacture of sulphuric acid by contact process.
(b) How will you test for sulphate ion ?
Answer:
From following steps sulphuric acid is manufactured
(i) SO₂ gas is produced by burning sulphur of FeS₂ in excess of air
S + O₂  → SO₂
4 FeS₂ +11O₂ → 2Fe₂ O₃ + 8SO₂

(ii) SO₂ is oxidised into SO₃ in prensence of catalyst
2 SO₂ + O₂ → 2 SO₃

(iii) SO₃ on treatment with cone. H₂SO₄ oleum (H₂S₂O₇) is obtained.
SO₃ + H₂SO₄  → 2 H₂S₂2O₇

(iv) From oleum sulphuric acid is obtained of desired concentration by diluting water.
H₂S₂O₇+ H₂O → 2H₂OSO₄

(b) Test of sulphate radical (of NO₂SO₄) – We mix up Barium chloride in the salt. We get white precipate of BaSO₄ which is insoluble in dil. HCl & HNO₃.
BaCl₂ 4- Na₂SO₄ → BaSO₄ ↓ +2 NaCl
BaCl₂ + HNO₃ → In soluble

Question 22.
What are carbohydrates ? How are they classified ?
Answer:
Carbohydrates are the naturally occuring organic compounds and are a major source of energy to our body. In plants carbohydrates are formed as a result for photosynthesis.

In animal systems the carbohydrates undergo decomposition to form carbon-dioxide and water accompanied by the release of energy needed for the body.

Composition of carbohydrates – The chemical formula of the carbohydrates suggests that these are the hydrates of carbon. For example, glucose may be represented as C₆(H₂O)₆ while sucrose as C₁₂(H₂O)₁₁ . But this definition has certain limitation.

(i) Compounds like formaldehyde (CH₂O) and acetic acid (C₂H₄O₂) are the hydrates of carbon do not show characteristics of carbohydrates.

(ii) Similarly, compound like rhammose (C₆H₁₂O₆) and deoxyribose (C₅H₁₀O₄) are carbohydrates but not the hydrates of carbon.

The definition of carbohydrates has been modified and they may be defined as—The polyhydroxy aldehydes or polyhdroxy ketones are substances which generally give these on hydrolysis; contain atleast one chiral carbon and are therefore, opitcally active classification of carbohydrates—

Classification of carbohydrates are done in three way

(a) Based on molecular size – on the basis of the molecular size, carbohydrates have been classified into three types. These are

• Manosaccharides
• Oligosoccharides
• Polysaccharides

Based on taste – Carbohydrates with sweet taste are called sugar while those without a sweet taste are called non-sugars. It may be noted that all mono and oligosaccharides are sugars while polysaccharides are non­sugar.

Reducing and non-reducing sugar –  Carbohydrate which reduce Tollen’s reagent and Fehling solution are called reducing sugar while those which don’t reduce, these are called non reducing sugars. For example – glucose and fructose.

Question 23.
Disuss the following :
(a) Kolbe’s reaction
(b) Wurtz’s reaction
(c) Carbylamine reaction.
Answer:
(a) Kolbe’s reaction – The reaction of phenoxide ion with CO₂ at the high pressure and temperature followed by acidification to form salicylic acid is called Kolbe’s reaction.

(b) Wurtz reaction-When two moles of alkyl halide is heated with Na in the presence of ether goes higher alkane.

(c) Carbylamine reaction-Chloroform when heated with primary amine in presence of alcoholic KOH forms a derivative called isocyanide.

Question 24.
Give one example for each of the following :
(a) Synthetic rubber
(b) Naturally occurring amino acid
(c) Condensation polymer
(d) Additional polymer
(e) Artificial sweeteners.
Answer:
(a) Nioprin
(b) Zwitter ion
(c) NYlon-6, 6
(d) Buna-5
(e) Saccharine.

 

Bihar Board 12th Physics Model Papers

Bihar Board 12th Physics Model Question Paper 5 in English Medium

Objective Type Questions

There are 1 to 35 objective type questions with 4 options. Choose the correct option which is to be answered on OMR Sheet. (35 x 1 = 35)

Question 1.
The electric field intensity at distance on the axis of an electric dipole is.Ej and E2 on the perpendicular bisector of dipole. The angle between E] and E2 is 6, will be
(a) 1 : 1, π
(b) 1 : 2, π/2
(c) 2 : 1, π
(d) 1 : 3 π
Answer:
(c) 2 : 1, π

Question 2.
The metre bridge is shown in figure. The value of x is
(a) 10Ω
(b) 3 ohm
(c) 9 ohm
(d) 10 ohm

Answer:
(a) 10Ω

Question 3.
The dimension of electromotive force is
(a) |ML² T^-3]
(b) [ML²T^-3I^-1]
(c) [MLT^-2]
(d) [ML²T^-3I^-1]
Answer:
(d) [ML²T^-3I^-1]

Question 4.
The power of electric circuit is
(a) V.R
(b) V2.R
(c) V2/R
(d) V2RI
Answer:
(c) V2/R

Question 5.
If a 60W and 40W bulb are joined in series the
(a) 60W bulb glow more
(b) 40 W bulb glow more
(c) Both bulb glow similar
(d) Only 60W bulb is lighted
Answer:
(b) 40 W bulb glow more

Question 6.
Kilowatt hour (kwh) is unit of
(a) Power
(b) Energy
(c) Torque
(d) None of these
Answer:
(b) Energy

Question 7.
A magnet is cut parallel to its length in n equal
parts. Magnetic moment of each part will be
\(\text { (a) } \frac{M}{n}\)
\(\text { (b) } \frac{M}{n^{2}}\)
\(\text { (c) } \frac{M}{2 n}\)
(d) None of these
Answer:
\(\text { (a) } \frac{M}{n}\)

Question 8.
The work done to rotate the magnet with 90° will be
(a) MB
(b) MB cosθ
(c) MB sin θ
(d) MB (1 – sin θ)
Answer:
(b) MB cosθ

Question 9.
S.I. unit of polar strength is
(a) Ampere metre
(b) Tesla
(c) Faraday
(d) Ampere gm²
Answer:
(a) Ampere metre

Question 10.
Which is ferromagnetic substance
(a) Mn
(b) Cr
(c) Zn
(d) Alnico
Answer:
(d) Alnico

Question 11.
Which law is based on the principle of conservation of energy?
(a) Lenz’s law
(b) Faraday’s law
(c) Ampere’s law
(d) None of these
Answer:
(a) Lenz’s law

Question 12.
The unit of reactance is
(a) mho
(b) ohm
(c) Faraday
(d) ampere
Answer:
(b) ohm

Question 13.
The phase difference between current and voltage in AC circuit is 0. Then power factor will
(a) cos θ
(b) sin θ
(c) tan θ
(d) 1θ
Answer:
(a) cos θ

Question 14.
The velocity of electro magnetic wave in air is

Answer:
(b)

Question 15.
The light waves are transverse in nature which is shown by
(a) Scattering
(b) Diffraction
(c) Interference
(d) Polarisation
Answer:
(d) Polarisation

Question 16.
When two converging lens of same total length / are placed in contact then focal length combination is
(a) f
(b) 2f
(c) f2
(d) 3f
Answer:
(c) f2

Question 17.
When the light ray passes from one medium to another medium then it is deviated, is called
(a) Dispersion
(b) Refraction
(c) Diffraction
(d) Reflection
Answer:
(b) Refraction

Question 18.
Convex lens are used for
(a) Myopia
(b) Hypermetropia
(c) Old sightedness
(d) Astigmatisn
Answer:
(b) Hypermetropia

Question 19.
The path difference for destructive interference is
(a) nλ
\(\text { (b) }(2 n+1) \frac{\lambda}{2}\)
(c) Zero
(d) infinity
Answer:
\(\text { (b) }(2 n+1) \frac{\lambda}{2}\)

Question 20.
Brewler’s law is
(a) μ = sin i_p
(b) μ = cos i_p
(c) μ = tan i_p
(d) μ = tan² i_p
Answer:
(c) μ = tan i_p

Question 21.
Light is made of vibration by
(a) Ether particle
(b) Air particle
(c) Electric and magnetic field
(d) None of these
Answer:
(c) Electric and magnetic field

Question 22.
Photo cell is based on
(a) photo electric effect
(b) chemical effect of current
(c) magnetic effect of current
(d) electromagnetic cell
Answer:
(a) photo electric effect

Question 23.
Which is uncharged
(a) α-particle
(b) β-particle
(c) photon
(d) proton
Answer:
(c) photon

Question 24.
Lymen series of Hydrogen lies in electromagnetic spectrum is
(a) X : ray
(b) Visible
(c) Infrared
(d) Ultra-violet
Answer:
(d) Ultra-violet

Question 25.
When transition takes place in hydrogen atom from higher orbit to another orbit then obtain
(a) Lymen series
(b) Balmer series
(c) Paschan series
(d) Pfund series
Answer:
(b) Balmer series

Question 26.
The average binding energy per nucleon of nucleus is
(a) 8 ev
(b) 8 Mev
(c) 8 Bev
(d) 8 Joule
Answer:
(b) 8 Mev

Question 27.
The cause of emission of energy in star is
(a) chemical reaction
(b) fusion of heavy nucleus
(c) fusion of light nucleus
(d) fission of heavy nucleus
Answer:
(c) fusion of light nucleus

Question 28.
The Boolean expression of OR gate is
(a) A + B = y
(b) A.B = y
\(\text { (c) } \bar{A}=y\)
\(\text { (d) } \mathrm{C}=\overrightarrow{\mathrm{A} \cdot \mathrm{B}}\)
Answer:
(a) A + B = y

Question 29.
The permeability of Ferromagnetic substance is
(a) μ > 1
(b) μ = 1
(c) μ < 1
(d) μ = 0
Answer:
(a) μ > 1

Question 30.
The light is emitted in forward biased junction diode, is called
(a) LED
(b) Photo diode
(c) Zener diode
(d) None of these
Answer:
(a) LED

Question 31.
Which expression is correct?

Answer:
(d)

Question 32.
The majority carriers in n-type semi conductor is
(a) proton
(b) hole
(c) a-particle
(d) electron
Answer:
(d) electron

Question 33.
Which frequency range is used for TV transmission?
(a) 30 HZ-300HZ
(b) 30 KHZ-300 KHZ
(c) 30 MHZ-300MHZ
(d) 30GHZ-300GHZ
Answer:
(a) 30 HZ-300HZ

Question 34.
Ionosphere is used for radio waves in
(a) rarer mediun
(b) denser medium
(c) free space
(d) dielectric
Answer:
(a) rarer mediun

Question 35.
The maximum distance upto which TV signal can be received from Antenna of height h is proportional to
(a) h^1/2
(b) h
(c) h^5/2
(d) h²
Answer:
(a) h^1/2

Non-Objective Type Questions!
Short Answer Type Questions

Question No. 1 to 18 are short answers type question. Each question carries 2 marks. Answer any ten (10) question.

Question 1.
Electric lines of force never intersect to each other. Why?
Answer:
If two lines of force intersect at a point then it will mean that at that point electric field has two directions. As it is not possible, the lines of force here not intersect to each other.

Question 2.
Write the limitations of Coulomb’s law.
Answer:
Coulomb’s law in electrostatics does not hold in all situation. It is applicable only in following situations :

1. The electric charges must be stationary.
2. The electric charge must be point in size. Coulomb’s law doesn’t apply to two charged bodies of finite size. It is because, the distribution of charge doesn’t remain uniform when the two bodies are brought together.

Question 3.
Prove maximum power theorem.
Answer:
It states that the output power of a source of emf is maximum, when the external resistance in the circuit is equal to the internal resistance of the source.

This is maximum power theorem.

Question 4.
Establish the relation b/w current density and drift velocity.
Answer:

Question 5.
What is Hysteresis loop? With its help explain the terms retentivity and co-ercivity.
Answer:
Hysteresis loop : Hysteresis loop is defined as the lagging of the magnetic induction B behind the corresponding magnetic field H.

When magnetic field H and the magnetic induction B are yarned from zero to maximum in one direction and then back through zero to a maximum in the opposite direction and finally back again through zero to the first maximum, a cycle of magnetisation is said to be completed. B(T) Y Using the value of H and B obtained above, we plot a graph by taking H along x-axis and B along y-axis. When the magnetic field H is increased from zero to the maximum value Og, the induction B follows the curve Oa. However, when the magnetic field is brought to zero, the.;induction does not follows back the curve Oa but a different curve ab. The same pattern of variations is seen for the rest of the curve. The B-H curve for decreasing H does not coincide with the B-H curve for increasing H.

As is clear from figure, even when the magnetising field H is zero, some magnetic induction (Ob or Oe) is still present in the speci nen. It is denoted by Br and is called remanance or retent i vity or residual magnetism.

The value of the intensity of magnetisation of a material when the magnetisi ng field is reduced to zero is called retentivity.

After the specimen has been magnetised to saturation (oh or oj) a reversed magnetising field (equal to Oc or Of) is required to reduce the magnetic induction to zero.This is called the coercivity or coercive force He. The value of the magnetising field required to reduce residual magnetism to zero is called coercivity of the material.

Question 6.
Write the expression for energy stored in the
Answer:
The induced emf in coil \(e=-L \frac{d I}{d t}\)
let chasge dq passes from coil, the work done dw = e.dq
\(\begin{aligned}
&=\mathrm{L} \cdot \frac{d I}{d t} d q=\mathrm{L} \cdot d I \cdot \frac{d q}{d t} \\
d w &=\mathrm{LI} . \mathrm{dI}
\end{aligned}\)

work done after posting current O to 1
\(\omega=\mathrm{L} \int_{0}^{1} I d I=\mathrm{L}\left[\frac{I^{2}}{2}\right]_{0}^{1} ; \omega=\frac{1}{2} \mathrm{L}^{2}\)

This work done is stored in the potential energy of coil.
\(P \cdot E=\frac{1}{2} L I^{2}\)

Question 7.
What is current sensitivity and voltage sensitivity of moving coil galvanometer?
Answer:
Current sensitivity : It is defined as the deflection produced in the galvanometer, when a unit voltage is applied across its cops.
\(\frac{\alpha}{\mathrm{I}}=\frac{\mathrm{nBA}}{\mathrm{K}}\)

Voltage sensitivity : It is defined as the deflection produced in the galvanometer, when a unit voltage is applied across its COPI.
\(\frac{\alpha}{V}=\frac{n B A}{K R}\)

Question 8.
Write the expression for energy density related with electro magnetic wave and show that its ratio is equal to 1.
Answer:

Question 9.
Sketch the wave front corresponding to (a)
diverging rays and (b) converging rays.
Answer:

Question 10.
Write the differences between magnification and magnifying power.
Answer:
Magnification :

• It is a linear magnification which is equal to \(\frac{n_{2}}{n_{1}}\).
• Its value increases with increase in V.
• It may be between to -∞ to +∞.
• Under certain conditions it is equal to magnifying power.

Magnifying power :
(i) It is an angular magnification which is equal to \(\frac{\angle \beta}{\angle \alpha}\)
(ii) Its value decreases with increase in V.
(iii) Its value may be b/w \(\frac{d}{f}\) and \(\left(1+\frac{D}{f}\right)\)
(iv) It is a special condition of magnification when (v_e = D

Question 11.
Derive the expression for de-Broglie wave length.
Answer:
A/C to quantum theory E = hv ……………………….. (i)

λ is called de-Broglie wavelength.

Question 12.
What is mass defect?
Answer:
Mass defect : The difference b/w sum of the masses of neutrons and protons forming a nucleus and actual mass of the nucleus is called mass defect.
Δm = [mpz + m_n (A – Z) – M]
The unit of mass defect is amu.

Question 13.
Why does thermionic emission takes place from metal surface only?
Answer:
Thermionic emission takes place from metal surface only because metal has free electrons on its surface.This free electrons requires less energy to come out from one surface. Also sometimes, to reduce work function of metal by coating oxide layer on metal.

Question 14.
Why is semi conductor damaged by a strong current?
Answer:
A strong current, when passed through a semi conductor, heat up the semi conductor and covalent bond break up. It results in a large number of free electrons. The material behaves as a conductor. As now the semi conductor no longer possesses the property of conduction, it is said to be damaged.

Question 15.
Write the differences between Intrinsic and extrinsic semi conductor.
Answer:
Intrinsic semi conductor :

• They are the crystals of pure elements like Germanium and Silicon.
• n_e = n_h
• The electrical conductivity of Intrinsic semi conductor is low.
• Resistivity is higher.

Extrinsic semi conductor:

• When some impurity is added in Intrinsic semi conductor, we get an extrinsic semi conductor.
• n_e ≠ n_h
• Its electrical conductivity is high.
• Resistivity is lower.

Question 16.
Define mean value and root square value A.C. Write its expression.
Answer:
Mean value of Average value : It is that steady current when passes through the circuit for half time period, sends the same amount of charge of the alternating current, sends the charge in same circuit and in same time period. It is denoted by Im.
\(\begin{aligned}
&I_{m}=\frac{2 I_{0}}{\pi}\\
&I_{m}=0.636 I_{0}
\end{aligned}\)

R.M.S. value or virtual value: It is that steady current when passes through the circuit for half time period, produces the same amount of heat as the alternating current produces the heat in same time and in same circuit. It is denoted by Irms.
\(\begin{aligned}
&I_{r m s}=\frac{I_{0}}{\sqrt{2}}\\
&I_{r m s}=0.7071
\end{aligned}\)

Question 17.
What is polaroids? Write its important uses.
Answer:
It is a device which produces plane polarised light. Use of polaroids :

• Sun glasses fitted with polaroid sheets protect the eye from glass.
• Wind shields of automobiles are also made of Polaroid sheets.
• They are useful in three dimensional motion pictures.
• It is used in L.C.D., calculator, watches, T.V. etc.

Question 18.
Write the condition for sustained interference.
Answer:
Condition for sustained interference :

• The two source should emf the light wave continuously.
• The light wave should be of same wave length.
• The two light source should be narrow.
• The light waves emitted should be of the same amplitude.
• The two source of light must lie very close to each other.

Long Answer Type Questions

Question No. 19 to 24 are long answers type question. Each question of this category carries 5 marks. Answer any three (3) question. (3 x 5 = 15)

Question 19.
Explain any two of the following terms :
(i) Ground Waves
(ii) Sky Waves
(iii) Space Waves.
Answer:
(i) Ground Waves : The ground waves which progress along the surface of the earth are called ground waves or surface waves. The ground propagation is suitable for low and medium frequency, i.e., up to 2 MHz only, hence it is also called medium wave propagation: The maximum range of ground or surface wave propagation depends on :

• The frequency of the radio waves and
• Power of the transmitter.

(ii) The Sky Waves : The sky waves are the radio waves of frequency between 2 MHz to 30 MHz. The ionosphere reflects those radio waves so that they can propagate through atmosphere. The sky waves propagation is also known as ionosphere propagation.

The sky waves are used for very long distance radio communication at medium high frequencies (i.e. at medium waves and short waves). The radio waves can cover a distance approximately 400 km in a single reflection from the ionosphere.

(iii) Space Waves : The space waves are the radio waves of very high frequency (i.e. between 30 MHz to 300 MHz or more). The space waves can travel through atmosphere from transmitter antenna to receive antenna either directly or after reflection from ground in the earth’s troposphere region. It is also called Tropospherical propagation or line of sight propagation. This propagation is limited (a) to the line of sight distance, (b) by the curvature of the earth.

It is utilized in T.V. communication, Radar communication, etc.

Question 20.
Find an expression for the electric field strength at a distant point situated (i) on the axis and (ii) along the equatorial line of an electric dipole.
Answer:
Consider an electric dipole AB. The charges -q and +q of dipole are situated at A and B respectively. The separation between the charges is 21.

Electric dipole moment, p = Q 21
The direction of dipole moment is from -q to + Q

(i) At axial or end-on position : Consider a point P on the axis of dipole at a distance r from mid-point O of electric dipole.

The distance of point P from charge + q is BP = r – l and distance of point P from charge – q is, AP = r + l. Let E₁ and E₂ be the electric field strengths at point P due to charges +<7 and -q respectively. We know that the direction of electric field due to a point charge is away from positive charge and towards the negative charge. Therefore

Clearly the directions of electric field strengths \(\overrightarrow{\mathrm{E}}_{1}\) and \(\overrightarrow{\mathrm{E}}_{2}\) are along the same line but opposite to each other and E₁ > E₂ because positive charge is nearer.

∴ The resultant electric field due to electric dipole has magnitude equal to the difference of E₁ and E₂ and direction from 13 to P i.e.

If the dipole is infinitely small and point P is far away from the dipole, then r >> l, therefore equation (i) may be expressed as
\(\mathrm{E}=\frac{1}{4 \pi \varepsilon_{0}} \frac{2 p r}{r^{4}} \text { or } \mathrm{E}=\frac{1}{4 \pi \varepsilon_{0}} \frac{2 p}{r^{3}}\) …………………………… (ii)

This is the expression for the electric field strength at axial position due to a short electric dipole.

Question 21.
Explain the principle and working of a Cyclotron with the help of a neat diagram. Write the expression for Cyclotron frequency.
Or,With the help of a labelled diagram, state the underlying principle of a Cyclotron. Explain clearly how it works to accelerate the charged particles.

Show that Cyclotron frequency is independent of energy of the particle. Is there an upper limit on the energy acquired by the particle? Give reason.
Answer:
(a) Cyclotron : The cyclotron, devised by Lawrence and Livingston, is a device for accelerating ions to high speed by the repeated application of accelerating potentials.

Construction:
The cyclotron consists of two flat semi-circular metal boxes called ‘dees’ and are arranged with a small gap between them. A source of ions is located near the mid-point of the gap between the dees (fig). The dees are connected to the terminals of a radio frequency oscillator, so that a high frequency alternating potential of several million cycles per second exists between the dees. Thus dees act as electrodes. The dees are enclosed in an insulated metal box containing gas at low pressure. The whole apparatus is placed between the poles of a strong electro¬magnet which provides a magnetic field perpendicular to the plane of the dees.

Working :
The principle of action of the apparatus is shown in fig.The positive ions produced from a source S at the centre are accelerated by a dees which is at negative potential at that moment. Due to the presence of perpendicular magnetic field the ion will move in a circular path inside the dees. The magnetic field and the frequency of the applied voltages are so chosen that as the ion comes out of a dees, the dees change their polarity (positive becoming negative and vice-versa) and the ion is further accelerated and moves with high velocity along a circular path of greater radius. The phenomenon is continued till the ion reaches at the periphery of the deeS where an auxiliary negative electrode (deflecting plate) deflects the accelerated ion on the target to be bombarded.

The function of electric field is to accelerae the charged particle and so to impart energy to the charged particle.

The function of magnetic field is to provide circular path to charged particle and so to provide the location where charged particle is capable of gaining energy from electric field.

Expression for Period of Revolution and Frequency :

Suppose the positive ion with charge q moves in a dees with a velocity v, then,
\(q v \mathrm{B}=\frac{m v^{2}}{r} \text { or }=\frac{m v}{q \mathrm{B}}\) …………………………… (i)

where m is the mass and r is the radius of the path of ion in the dees and B is the strength of the magnetic field. The angular velocity to of the ion is given by.
\(\omega=\frac{v}{r}=\frac{q \mathrm{B}}{m}( \text { from eq. }\) ………………… (ii)

The time taken by the ion in describing a semi-circle, i.e., in turning through an angle π is.
\(t=\frac{\pi}{\omega}=\frac{\pi m}{\mathrm{B} q}\)

Thus the time is independent of the speed of the ion i.e., although the speed of the ion goes on increasing with increase in the radius (from eQuestion i) when it moves from one dees to the other, yet it take the same time in each dees.

From eQuestion (iii) it is clear that for a particular ion, \(\frac{m}{q}\)

being known, B can be calculated for producing resonance with the high frequency alternating potential.

(b) Resonance Condition : The condition of working of cyclotron is that the frequency of radio frequency alternating potential must be equal to the frequency of revolution of charged particles within the dees. This is called resonance condition.

Now for the cyclotron to work, the applied alternating potential should also have the same semiperiodic time (T/2) as that taken by the ion to cross either dees, i.e.,

This is the expression for period of revolution. Obviously, period of revolution is independent of speed of charged particle and radius of circular path.

∴ Frequency of revolution of particles.
\(f=\frac{1}{T}=\frac{q B}{2 \pi m}\)

This frequency is called the cyclotron frequency. Clearly the cyclotron frequency is independent of speed of particle.

(c) Expression for K.E. attained : If R be the radius of the path and Vmax, the velocity of the ion when it leaves the periphery, then in accordance with eq (ii)
\(v_{\max }=\frac{q \mathrm{BR}}{m}\) …………………………….. (vi)

The kinetic energy of the ion when it leaves the apparatus is,
\(\text { K.E. }=\frac{1}{2} m v^{2} \max =\frac{q^{2} B^{2} R^{2}}{2 m}\) ………………….. (vii)

When charged particle crosses the gap between dees it gains KE = qV

In one revolution, it crosses the gap twice, therefore if it completes ^-revolutions before emerging the dees, the kinetic energy gained = 2nqV ………………. (viii)
\(\text { Thus, K.E. }=\frac{g^{2} \mathrm{B}^{2} \mathrm{R}^{2}}{2 m}=2 n q \mathrm{V}\)

Question 22.
Using Ampere’s circuital law, derive an expression for the magnetic field along the axis of a toroidal solenoid.
Answer:
Magnetic field due to a toroidal solenoid : A long solenoid shaped in the form of closed ring is called toroidal solenoid (or endless solenoid). Let n be the number of turns per unit of toroid and I the current flowing through it. The current causes the magnetic field inside the turns of the solenoid. The magnetic lines of force inside the toroid are in the form of concentric circle. By symmetry of the magnetic field it has the same magnitude at each point of circle and is along the tangent at every point on the circle.

For points inside the core of toroid: Consider a circle of radius r in the region enclosed by turns of toroid. Now we apply Ampere’s circuital law to this circular path, i.e.,
\(\vec{f} \overrightarrow{\mathrm{B}} \cdot \overrightarrow{d l}=\mu_{0} I\) ………………. (i)

\(\vec{f} \overrightarrow{\mathrm{B}} \cdot \overrightarrow{d l}=f B d l \cos 0=B \cdot 2 \pi r\) Length of toroid = 2πr Number of turns in toroid = n (2πr) and current in one- turn = I.

∴ Current enclosed by circular path = (n 2πr) • 1
∴ Equation (i) gives
\(\mathrm{B} 2 \pi r=\mathrm{m}_{0}(n 2 \pi r l) \Rightarrow \mathrm{B}=\mu_{0} n \mathrm{l}\)

Derivation of formula for magnetic field due to a current carrying wire using Biot-Savart law : Consider a wire EF carrying current I in upward direction. The point of observation is P at a finite distance R from the wire. If PM is perpendicular dropped from P on wire; then PM = R. The wire may be supposed to be formed of a large number of small current elements. Consider a small element CD of length δf at a distance f from M.

\(\text { Let } \angle \mathrm{CPM}=\phi \text { and } \angle \mathrm{CPD}=\delta \phi, \angle \mathrm{PDM}=\theta\) The length δf is very small, so that ∠PCM may also be taken as equal to θ.

The perpendicular dropped from C on PD is CN.

The angle formed between element I \(\overrightarrow{\delta l}\) and \(\overrightarrow{r}\) (= cp is (π – θ), Therefore according to Biot-Savart law, the magnetic field due to current element I \(\overrightarrow{\delta l}\) at P is

If the wire is of finite length and its ends make angles a and p with line MP, then net magnetic field (B) at P is obtained by summing over magnetic fields due to all current elements, i.e.,

This is expression for magnetic field due to current carrying wire of finite length (or very long), then α = β ⇒ π/2.

Question 23.
Draw the labelled ray diagram for the formation of image by a compound microscope.
Derive an expression for its total magnification (or magnifying power), when the find image is formed at the near point.
Why both objective and eye piece of a compound microscope must have their short focal lengths?
Answer:
Compound Microscope :
It consists of a long cylindrical tube, containing at one end of a convex lens of small aperture and small focal length. This is called the objective lens (O). At the other end of the tube another co¬axial smaller and wide tube is fitted which carries a convex lens (E) at its outer end. This lens is towards the eye and is called the eye-piece. The focal length and aperture of eye piece are somewhat large than those of objective lens. Cross¬wires are mounted at a definite distance before the eye piece. The entire tube can be moved forward and backward by the rack and pinion arrangement.

Magnifying power of a microscope:
is defined as the ratio of angle ((3) subtended by final image on the eye to the angle (a) subtended by the object on eye, when the object is placed at the least distance of distinct vision, i.e.,

Magnifying power \(M=\frac{\beta}{\alpha}\)

As object is very small, angles α and β are very small and so tan α = α and tan β = β. By  efinition the object AB is placed at the least distance of distinct vision

Question 24.
State the principle of working of p-n diode as a rectifier. Explain with the help of a circuit diagram, the use of p-n diode as full wave rectifier. Draw a sketch of the input and output wave forms. Or, Draw a circuit diagram of a full wave rectifier. Explain the working principle. Draw the input/output wave forms indicating clearly the functions of the two diodes used.
Answer:
Rectification :
Rectification means conversion of a.c. into d.c. A p-n diode acts as a rectifier because an ac changes polarity periodically and a p-n diode conducts only when it is forward biased; it does not conduct when reverse biased.

In a full wave rectifier, if input frequency is / hertz, then output frequency will be 2/ hertz because for each cycle of input, two positive half cycles of output are obtained.

Working:
The AC input voltage across secondary s₁ and s₂ cli anges polarity after each half cycle. Suppose during the first half cycle of input AC signal, the terminal s₁ is positive relative to centre tap O and s₂ is negative relative to O. Then diode D₁ is forward biased and diode D₂ is reverse biased. Therefore diode D₁ conducts while diode D₂ does not. The direction of current (i₁) due to diode D₁ in load rsistance R_L is directed from A to 13. In next half cycle, the terminal s is negative and s₂ is positive relative to centre tap O.

The diode D is reverse biased and diode D₂ is forward biased. Therefore, diode D₂ conducts while D₁ does not. The direction of current (i₂) due to diode D₂ in load resistance R_L is still from A to B. Thus the current in load resistance R_L is in the same direction for both half cycles of input AC voltage. Thus for input AC signal the output current is a continuous series of unidirectional pulses.

In a full wave rectifier, if input frequency is f hertz, then output frequency will be 2f hertz because for each cycle of input, two positive half cycles of output are obtained.