Category: Class 12

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 Entrepreneurship Model Papers

Bihar Board 12th Entrepreneurship Model Question Paper 1 in English Medium

Time: 3 Hours 15 Min
Marks: 70

Instructions for the candidates:

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 35 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/Nail on OMR Sheet, otherwise, the result will be treated as invalid.
6. In Section – B, there are Non-objective type questions. There are 18 Short answer type questions, out of which any 10 questions are to be answered. Each question carries 2 marks. Apart from this, there are 6 Long answer type questions, out of which any 3 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 35 has 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. (35 × 1 = 35)

Question 1.
The term ‘Fund’ as used in Fund Flow Analysis means:
(a) Cash only
(b) Current Assets
(c) Current Liability
(d) Excess of current Assets over Current Liabilities.
Answer:
(d) Excess of current Assets over Current Liabilities.

Question 2.
Networking capital means:
(a) C.A – C. L.
(b) C.A. + C.L.
(c) C. L. – C.A.
(d) None of the above
Answer:
(a) C.A – C. L.

Question 3.
A. E. P. = _________
(a) \(\frac { FixedCost }{ \frac { P }{ V } Ratio }\)
(b) \(\frac { FixedCost }{ \frac { P }{ V } Ratio } \times 100\)
(c) \(\frac { \frac { P }{ V } Ratio }{ FixedCost }\)
(d) None of these
Answer:
(b) \(\frac { FixedCost }{ \frac { P }{ V } Ratio } \times 100\)

Question 4.
Risk Capital Foundation was established in
(a) 1970
(b) 1975
(c) 1986
(d) 1988
Answer:
(b) 1975

Question 5.
Capital Intensive technique is favoured due to:
(a) Rapid economic growth
(b) Social influence
(c) Increase in employment opportunities
(d) All of the above
Answer:
(d) All of the above

Question 6.
Management is an art of:
(a) doing work himself
(b) taking work from others
(c) both for doing work himself and taking work from others
(d) All
Answer:
(c) both for doing work himself and taking work from others

Question 7.
Out of the following which is the method of quality control?
(a) Inspection method
(b) Statistical Quality Control Method
(c) Both A and B above
(d) Neither A nor B above
Answer:
(c) Both A and B above

Question 8.
Dividend paid on cumulative preference share:
(a) In the year of profit
(b) In the year of loss
(c) In the year of profit or loss
(d) None of these
Answer:
(a) In the year of profit

Question 9.
The best example of variable cost is:
(a) Interest on capital
(b) Material cost
(c) Wealth tax
(d) Rent
Answer:
(b) Material cost

Question 10.
Generally, diversification is classified in
(a) Two ways
(b) Three ways
(c) Four ways
(d) Five ways
Answer:
(c) Four ways

Question 11.
Is it necessary to give due consideration on internal resources
(a) Yes, it is necessary
(b) No, not necessary
(c) Necessary for external resources
(d) None of the above
Answer:
(a) Yes, it is necessary

Question 12.
Incentives are not concerned with:
(a) Rebate
(b) Exemption from Tax
(c) Provision of seed capital
(d) Lump-sum payment
Answer:
(c) Provision of seed capital

Question 13.
Which of the following is known as Market Demand?
(a) Demand Forecasting
(b) Real Demand
(c) Supply
(d) None of the above
Answer:
(a) Demand Forecasting

Question 14.
Which of the following factors are to be considered while selecting a product or service?
(a) Competition
(b) Cost of production
(c) Profit possibility
(d) All of the above
Answer:
(d) All of the above

Question 15.
Selection of an enterprise depends on:
(a) Sole Trading
(b) Right of Entrepreneur
(c) Self Ability of Entrepreneur
(d) None of the above
Answer:
(d) None of the above

Question 16.
An entrepreneur prefers which form of an organization if production is to be undertaken on a small scale basis?
(a) Sole Trader
(b) Partnership
(c) Company
(d) None of the above
Answer:
(a) Sole Trader

Question 17.
Project identification deals with:
(a) Viable Product idea
(b) Logical opportunity
(c) Effective demand
(d) None of these
Answer:
(a) Viable Product idea

Question 18.
The techno-economic analysis deals with the identification of the
(a) Supply potential
(b) Demand potential
(c) Export potential
(d) Import potential
Answer:
(b) Demand potential

Question 19.
Project appraisal is an/a
(a) Export Analysis
(b) Expert Analysis
(c) Profitability Analysis
(d) None of the above
Answer:
(c) Profitability Analysis

Question 20.
Various public utility undertaking has to invest heavily in:
(a) Current Assets
(b) Fixed Assets
(c) Fictitious Assets
(d) None of the above
Answer:
(b) Fixed Assets

Question 21.
Pay-back period deals with:
(a) The period required for-profit earning process
(b) The period required for the cost of investment recovery
(c) The period required for fixed cost recovery
(d) None of the above
Answer:
(b) The period required for the cost of investment recovery

Question 22.
The project life cycle is not concerned with the following:
(a) Pre-investment stage
(b) Constructive stage
(c) Normalisation stage
(d) Stabilisation stage
Answer:
(d) Stabilisation stage

Question 23.
Which of the following is the main problem connected with business?
(a) Profit
(b) money
(c) Sales
(d) Risk Management
Answer:
(d) Risk Management

Question 24.
What creates perfection in .the market which ultimately increases the volume of sales & profit?
(a) Innovation
(b) Promotion
(c) Marketing
(d) None of the above
Answer:
(c) Marketing

Question 25.
Short-term forecast involves a period of how many months?
(a) 12 months
(b) 24 months
(c) 18 months
(d) 36 months
Answer:
(a) 12 months

Question 26.
Business Regulatory framework is concerned with what
(a) Direction of Business
(b) Volume of Business
(c) Regulation
(d) None of the above
Answer:
(b) Volume of Business

Question 27.
The product which is more in demand are more
(a) Less profitable
(b) Possible
(c) More profitable
(d) None of the above
Answer:
(c) More profitable

Question 28.
Out of the following formulating of the general plan of a business depends?
(a) Project Report
(b) Plant and Product Planning
(c) Marketing Planning
(d) Financial Planning
Answer:
(d) Financial Planning

Question 29.
What break-even point shows:
(a) Profit
(b) Loss
(c) Neither Profit nor Loss
(d) None of these
Answer:
(c) Neither Profit nor Loss

Question 30.
The best example of Fixed cost is:
(a) Interest on capital
(b) Material cost
(c) Wealth Tax
(d) None of these
Answer:
(a) Interest on capital

Question 31.
What is the thing that enterprise do? The paths they follow and the decision they take in order to reach certain points and levels of success:
(a) Production
(b) Distribution
(c) Marketing
(d) Strategies
Answer:
(d) Strategies

Question 32.
Out of the following, what is essential to study in the feasibility study?
(a) Cost
(b) Price
(c) Operation
(d) All of the above
Answer:
(d) All of the above

Question 33.
What is included in the nature of marketing?
(a) Product Planning
(b) Classification of product
(c) Consumer
(d) Customer
Answer:
(c) Consumer

Question 34.
Social behaviour is not concerned with:
(a) Production of goods for public
(b) Avoidance of unethical behaviour
(c) Fulfilment of social obligations.
(d) Profit earning process
Answer:
(d) Profit earning process

Question 35.
Business opportunity relates to:
(a) Commercially feasible project
(b) Personal feasible projects
(c) Neither A nor B above
(d) None of the above
Answer:
(a) Commercially feasible project

Non-Objective Type Questions

Short Answer Type Questions

Question No. 1 to 18 are short answer type. Answer any 10 questions. Each question carries 2 marks. (10 × 2 = 20)

Question 1.
Why is entrepreneurship regarded as a creative activity?
Answer:
Entrepreneurship is creative in the sense that it involves the creation of value. By combining the various factors of production, entrepreneurs produce goods and services that meet the needs and wants of society. Every entrepreneurial act results in income and wealth generation. Even when innovations destroy the existing industries.

Entrepreneurship is creative also in the sense that it involves innovation introduction of new products, the discovery of new market and sources of supply of inputs, technological break thoughts as well as the introduction of newer organisational forms for doing things better, cheaper, faster and in the present context, in a manner that causes the least harm to the environment. It is possible that entrepreneurs in developing countries may not be pioneering innovative in introducing path-breaking, radical innovations.

Question 2.
What do you understand by Micro Environment?
Answer:
The microenvironment is the first pillar to build a business empire. All marketing plans, strategies and objectives are carried out through these components. It is, therefore, the executive arm of business where the practical implementation of ideas, thoughts, and concepts are done and based on the responses of these components, a business either moves forward or may step back.

Question 3.
What do you mean by market environment?
Answer:
Marketing Environment is the combination of external and internal factors and forces which affect the company’s ability to establish a relationship and serve its customers. The marketing environment of a business consists of an internal and external environment.

Question 4.
What is the object of project appraisal?
Answer:

• To extract relevant information for determining the success or failure of a project.
• To apply standard yardsticks for determining the rate of success or failure of a project.
• To determine the expected costs and benefits of the projects.
• To arrive at specific conclusions regarding the project.

Question 5.
What is factoring?
Answer:
Factoring is a transaction in which a business sells its invoices, or receivables, to a third-party financial company known as a “Factor”.
Factoring is known in some industries as “accounts receivables financing”.

Question 6.
Give the definitions of Fund Flow Statement.
Answer:
A fund flow statement is a statement prepared to indicate the increase in the cash resources and the utilisation of such resources of business during the accounting period.

Question 7.
What do you mean by Ratio Analysis?
Answer:
Ratio analysis is the process of determining and interpreting numerical relationships based on financial statements. A ratio is a statical yardstick that provides a measure of the relationship between variables or figures. This relationship can be expressed as a percent.

Question 8.
How is break-even point determined?
Answer:
Break-even analysis related to the study of cost and return investment in relation to the sales of a business unit. That point or level of sales at which the business makes no profit and no loss is termed as the break-even point. Break-even point can be applied from two viewpoints- Narrow viewpoint and broad viewpoint, from the narrow viewpoint break-even analysis is a technique which determines that level of work at which the total return is equal to total expenditure. That is why this is known as the point of no profit no loss.
Break-point is the point at which the following characteristics are observed:

• The firm is neither earning any profit nor undergoing any loss i.e. it is in a state of no profit no loss.
• The total return of the firm is equal to the total cost.
• Amount of contribution (Sales-variable cost is) equal to the fixed cost.

Because of the above characteristics of the break-even point, it is also known as ‘Equilibrium point’ or ‘balancing point’ ore ‘critical point’.

Question 9.
Who is an Entrepreneur?
Answer:
The term ‘entrepreneur’ was first introduced in economics by the early 18th-century French economist Richard Cantillon. The entrepreneur as the agent who buys means production at certain prices in order to sell the produce at uncertain prices in the future. “ Since then a perusal of the usage of the term in economics shows, that entrepreneurship implies risk uncertainty bearing coordination of productive resources; introduction of innovation; and the provision of capital.

Question 10.
State the two objectives of identification of business opportunities.
Answer:
Following are the objectives of identifying business opportunities:

• Identify the sources of business ideas.
• Explain methods for generating business ideas.
• Identify various entrepreneurial opportunities.
• Understand the nature of the occupational and geographical mobility of entrepreneurs.

Question 11.
Give any two objectives of environmental scanning.
Answer:
Two objectives of environment scanning are mention below.

• Environmental scanning is the process of gathering information about the event and their relationship within an organisation’s internal and external environments.
• Environmental scanning is to help management determine the future direction of the organisation.

Question 12.
Mention any two objects of the project report.
Answer:
Two objectives of project report are following.

• To evaluation of environment opportunity.
• It is necessary to present the report for taking financial help.

Question 13.
What do you’re mean by the cycle of working capital?
Answer:
Availability of enough working capital is indicative of liquidity of business and capacity to make prompts payment. Working capital is needed for making payment of day to day expenditure for meeting current liabilities and for availing benefit of cash discount.

Question 14.
Why time boundness is essential in a project?
Answer:
Project is a written account of various activities undertaken by a firm or entrepreneurs and their technical, commercial and social feasibilities. Project is made after analysis of essential document therefore there is a time limit for making project because of the project is made for particulars time and subject.

Question 15.
What is the marketing mix?
Answer:
Marketing mix implies a combination of all marking elements or ingredients so that the objective of the enterprise may be realised. The marketing mix is the appointment of effort the combination the designing and the integration of the elements of marketing into a programme or mix which on the basis of the marketing forces will best achieve the objectives of an enterprise at a given time.

Question 16.
List any two problems faced by first-generation entrepreneurs?
Answer:
List of problems faced by first-generation entrepreneurs.

• Business ideas issues.
• Lack of finance.
• Inability to market their business.
• Not knowing how to plan the business.
• Legal question.

Question 17.
What do you mean by market assessment?
Answer:
Market Assessment: Goods are produced and facilitate for providing services are created in anticipation of their demand the ultimate aim of these activities is that these reach these for whose these are meant. The commodities are needed for consumption and used by the ultimate consumers. The services are utilized by whose Who was want to derive satisfaction out of them.

Question 18.
What is market observation?
Answer:
Market observation is a market research techniques in which highly trained researchers generally watch how people or consumers behave and interact in the market under natural conditions. It is designed to give precisely detailed and actual information on what consumers do as niche.

Long Answer Type Questions

Question No. 19 to 24 are long answer type. Answer any 3 questions. Each question carries 5 marks. (3 × 5 = 15)

Question 19.
Why the environmental study is essential for an entrepreneur?
Answer:
The process of environmental scanning and analysis is very important to an entrepreneur. The evaluation of the existing changing circumstances the forecasting and the consequent impacts need to be assessed by an entrepreneur prior to determining his policies and planning and their successful implementation. It is essential to evaluate and analyse the consequences of the changing business environment prior to giving a tangible shape to the planning and policies.

The technical innovation, new social values, problems of the community, product – market conditions etc. Must be subjected to study which is instrumental in converting strategies and planning into reality. The competitive environment and its consideration is also an integral part of environmental scanning. To plan or conceive the counter-strategies in view of the competitive threats, the environmental study and analysis is the pre-requisite in this regard by a close study and a survey of the competitive threats, the environmental.

Question 20.
How would you execute the set up of an enterprise?
Answer:
The study of these five constituents is essential for the emergence of an enterprise.

• Labour or men: In all the resources of production, the ingredient of labour is the most mobilising element that stimulates all other factors and turns even the most useless thing into a useful one.
• Raw material: If the enterprise is production oriented a prior arrangement should be emphasised with regard to availability, type, cost/price and regular supply of the raw materials.
• Machine: Whatever be the scale of the enterprise whether big or small, machines are required in either case.
• Money: Money/capital is the lifeblood of an enterprise without which the establishment is an inconceivable presumption. The capital in the long and short term and its amount and the capital resources are a pre-emptive requirements
• Market: A prior estimate is to be formed in terms of the market-consumption before the establishment of the enterprise.
• Place: It is also an important aspect and be decided where the enterprise should be set up.

Question 21.
What problems should be properly considered in the expansion of a business enterprise? Elucidate.
Answer:
(i) Cash flow management: Cash flow problems are the second most common reason why small businesses go but according to research from CB Insights. Owners have to spend money to make money during a growth period, but this concept can quickly get out of control and leave you in a precarious position.

(ii) Responding to the competition: A funny thing happens when your company is successful- others recognize the opportunity and enter the industry. Many small business owners are unprepared for the realities of fierce competition, and they quickly lose their way in an attempt to respond.

(iii) Nurturing a great company culture: Your company culture is affected by everyone involved with your organization. As you grow and more people come into your company’s orbit, it becomes more difficult to exert control over your culture and you run the risk of having it drailed.

(iv) Learning when to delegate and when to get involved: There are times when entrepreneurs need to get personally involved in specific decisions, such as big – picture strategic planning and hiring for key positions. Then there are times where it is important to delegate and trust that your managers will make the best decision for their team and the company.

(v) Keeping up with market changes: If your company operates in a sector that experiences frequent upheaval, you have to be prepared for constant change. Internalize the idea that disruption is the new normal and work on training your employees to be agile in the face of uncertainty.

(vi) Deciding when to abandon a strategy: Sometimes marketing channels that seemed full of potential don’t pan out and new product lines don’t catch on as anticipated failures are an important part of business growth and owners must train themselves to recognize where they occur, divert resources accordingly and learn from those mistakes.

Question 22.
Describe the factors affecting working capital.
Answer:
Factors affecting the working capital:
There are the following factors affecting the working capital as:
(i) Nature and size of Business: The working capital depends on the nature of the business to a great extent. If a business is engaged in the production process more working capital will be required on other hand business firms engaged in trade activities will ‘require less working’ capital.

(ii) Business cycles: The need for working capital keeps on increasing or decreasing according to the business cycle. During Boom periods the businessman tries to keep the maximum possible stock of goods in order to escape from the price increase.

(iii) Term of Buying & Selling: If businessman buy the necessary material for cash he requires more working capital. If the business unit has the policy of credit sales, more working capital will be required.

(iv) Duration of Production: The amount of working capital also depends upon the time taken in the manufacturing of a product. If the time required for the manufacture of the product is more, more working capital is needed to be.

(v) Volume & Procurement of Raw Material: If the amount to be spent on raw material is more in total investment more working capital will be required.

(vi) Manual Vs Automation: If a business unit uses automatic machines for production less working capital will be required. If the production is labour oriented like the workers engaged in tea, coffee, rubber etc. More working capital will be required.

(vii) form of Taxation: Government policy of taxation also influences the need for working capital more capital will be required if all taxes are to be paid in advance, otherwise, the need will be less.

(viii) Seasonal goods: If business units are engaged in such goods in which seasonal conditions play an important role need for working capital will be felt according to seasonal requirements.

(ix) The intensity of competition: If the market competition is intense, more amount of working capital is required as a competitive firm has to keep huge quantities of a long-range of products.

(x) Business growth: If a business is expanding it requires more money for raw materials wages etc.

Question 23.
What are the factors affecting the identification of business opportunities?
Answer:
Responsibilities of each entrepreneur of the environment are any kind of tampering with the environment in terms of filing, pollution, contamination, etc. is a serious offence which is causing great harm to the present generation. In assertion, it is raising a question mark on the fate of the coming generation. No doubt, the industrial units do cause pollution, more or less, to the environment, and it is the prime responsibility of an entrepreneur not to harm the environment in any way. The industrial waste, raw residual, etc., must not be thrown into the water, its right use should be encouraged. Personal profit should not be the sole consideration here to the extent that the environment is polluted. The government is very serious about it and does not permit, even then an entrepreneur ought to be considerate at his own in this regard.

Question 24.
Explain the meaning, definition and objective of Financial Management.
Answer:
The financial manager in order to achieve the objectives of financial management performs many functions:
(i) Estimating the financial requirements: The financial manager has to estimate the financial requirements both for long and short periods. The long term financial needs means for procuring fixed assets and part of current assets and short term requirements are meant for providing the current assets.

(ii) The decision about capital structure: After estimating the longterm financial requirements the next step is to decide about the sources from where these funds would be raised. The financial manager explores and assesses the various long-term sources in the light of requirements of the enterprise and then decides what specific sources to tap and low much to raise form each of these in the overall interest of the organisation.

(iii) Dividend Decision: It is for the finance manager to make suggestions in respect of dividend payment. He looks into the trends of earnings, share market prices the funds required for future growth, the cash flow situation, etc and recommends to the top management how much of earnings should be earmarked for payment of dividend and how much should be retained in the business.

(iv) Cash management: The finance manager has to ensure that adequate cash is available for various purposes with minimum cost, that the rate of cash inflow is accelerated and that of cash outflow decelerated, that suitable arrangements exit for meeting situation of foreseen or unforeseen shortage of cash and that adequate steps are taken to keep at the bare minimum level cash lying idle with the cashier and or at the bank.

(v) Report with investors: Many parties like financial institutions, banks, underwriters, public etc. Invest money in the organisation, the finance manager establishes close links with them, supplies them the necessary information and negotiates to get financial assistance from them.

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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.