Category: Class 12

Bihar Board 12th Maths Model Papers

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

Time : 3 Hours 15 Min
Full Marks: 100

Instructions for the candidates :

1. Candidates are required to give their answers in their own words as far as practicable.
2. Figure in the right-hand margin indicates full marks.
3. While answering the questions, the candidate should adhere to the word limit as far as practicable.
4. 15 Minutes of extra time has been allotted for the candidate 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 1-50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with blue/black ball pen against the correct option on the OMR Sheet provided to you. Do not use Whitener/Liquid/ Blade/Nail on OMR Sheet otherwise result will be invalid.
7. In section-B, there are 25 short answer type questions (each carrying 2 marks), out of which only 15 (fifteen) questions are to be answered.
   A part from this there is 08 Long Answer Type questions (each carrying 5 marks), out of which 4 questions are to be answered.
8. Use of any electronic device is prohibited.

Objective Type Questions

There are 1 to 50 objective type questions with 4 options, choose the correct option which, is to be answered on OMR Sheet. (50 x 1 = 50)

Question 1.
Which of the following has its inverse function one-one and onto?
(a) one-one onto
(b) one-one into
(c) many one onto
(d) many on into
Answer:
(a) one-one onto

Question 2.
A relation R in a set X is an equivalence relation if R is
(a) reflexive
(b) symmetric
(c) transitive
(d) All of above
Answer:
(d) All of above

Question 3.
The number of all one-one functions from set {a, b, c, d} to itself is
(a) 12
(b) 24
(c) 36
(d) None
Answer:
(b) 24

Question 4.
If \(-\frac{\pi}{2}<x<\frac{\pi}{2}\) then tan(tan^-1 x) =
(a) tan x
(b) cotx
(c) x
(d) -x
Answer:
(c) x

Question 5.
Sin^-1 x + Cos^-1 y =
(a) 0
(b) \(\frac{\pi}{4}\)
(c) \(\frac{\pi}{2}\)
(d) π
Answer:
(c) \(\frac{\pi}{2}\)

Question 6.
If x > 0, y > 0, xy < 1, then tan^-1x + tan^-1 y =
(a) tan^-1 (x+y)
(b) \(\tan ^{-1} \frac{x+y}{1-x y}\)
(c) tan^-1
(d) sin^-1(x + y)
Answer:
(b) \(\tan ^{-1} \frac{x+y}{1-x y}\)

Question 7.
(a) tan^-12x
(b) \(\tan ^{-1} \frac{2 x}{1-x^{2}} \)
(c) \(\tan ^{-1} \frac{2 x}{1+x^{2}}\)
(d) \(\cot ^{-1} \frac{2}{x}\)
Answer:
(b) \(\tan ^{-1} \frac{2 x}{1-x^{2}} \)

Question 8.
\(2\left[\begin{array}{ll}
x & y \\
1 & m
\end{array}\right]\) =

Answer:
(c) \(\left[\begin{array}{cc}
2 x & 2 y \\
1 & 2 m
\end{array}\right]\)

Question 9.
\(5\left|\begin{array}{ll}
2 & 3 \\
3 & 4
\end{array}\right|=\)

Answer:
\(\left|\begin{array}{cc}
2 & 3 \\
15 & 20
\end{array}\right|\)

Question 10.
If A = \(\left[\begin{array}{cc}
5 & -5 \\
5 & -5
\end{array}\right]\) then A’ =

Answer:
(c) \(\left[\begin{array}{cc}
5 & 5 \\
-5 & -5
\end{array}\right]\)

Question 11.
\(\left|\begin{array}{ll}
1 & 0 \\
0 & 1
\end{array}\right|=\)
(a) 0
(b) 1
(c) -1
(d) 2
Answer:
(b) 1

Question 12.
\(\left[\begin{array}{ll}
\mathbf{a} & \mathbf{b} \\
\mathbf{c} & \mathbf{d}
\end{array}\right]+\left[\begin{array}{ll}
\mathbf{p} & \mathbf{q} \\
\mathbf{r} & \mathbf{s}
\end{array}\right]=\)

Answer:
\(\left[\begin{array}{cc}
a+p & b+q \\
c+r & d+s
\end{array}\right]\)

Question 13.
For a non-invertible matrix A,
(a) | A | = 0
(b)|A|≠ 0
(c) | A | = 1
(d) | A | = 2
Answer:
(b)|A|≠ 0

Question 14.
If 1 is an unit matrix of order 2 × 2 then I³ =
(a) 3I²
(b) 3 + I
(c) 3I
(d) I
Answer:
(d) I

Question 15.
If A = \(\left[\begin{array}{ll}
2 & 3 \\
4 & 5
\end{array}\right]\) and \(\left[\begin{array}{ll}
4 & 6 \\
8 & 10
\end{array}\right]\) then 2A – B =
(a) [0]
(b) [0,0]
(c) \(\left[\begin{array}{ll}
0 & 0 \\
0 & 0
\end{array}\right]\)
(d) [3]
Answer:
(c) \(\left[\begin{array}{ll}
0 & 0 \\
0 & 0
\end{array}\right]\)

Question 16.
If the order of two matrices A and B are 2×4 and 3×2 respectively then the order of AB is
(a) 2 x 2
(b) 4 x 3
(c) 2 x 3
(d) it is not possible to find AB
Answer:
(d) it is not possible to find AB

Question 17.
\(\frac{d}{d x}(\tan x)=\) =
(a) cot x
(b) Sec²x
(c) Secx tanx
(d) Secx
Answer:
(b) Sec²x

Question 18.
\(\frac{d}{d x}\left(\sin ^{3} x\right)=\)
(a) 3 cos³
(b) 3 sin²xcosx
(c) 3sin²x
(d) cos³x
Answer:
(b) 3 sin²xcosx

Question 19.
\(\frac{d}{d x}\) [3 (sin² x + cos²x )] =
(a) 3
(b) 1
(c) 0
(d) 6 sin x cos x
Answer:
(c) 0

Question 20.
\(\frac{d}{d x}\) (e^4x) =
(a) e^4x
(b) e^x
(c) \(\frac{e^{4 x}}{4}\)
(d) 4e^4x
Answer:
(d) 4e^4x

Question 21.
\(\frac{d}{d x}\left(x^{5}\right)=\)
(a) 5x⁵
(b) 5x⁴
(c) \(\frac{x^{6}}{6}\)
(d) \(\frac{x^{4}}{4} \)
Answer:
(b) 5x⁴

Question 22.
\(\frac{d}{d x}\) [log(x³)] =
(a) \(\frac{1}{x^{3}}\)
(b) \(\frac{3}{x}\)
(c) 3x
(d) \(\frac{3}{x^{3}}\)
Answer:
(b) \(\frac{3}{x}\)

Question 23.
If x= cosθ,y = sinθ then \(\frac{d y}{d x}\) =
(a) tanθ
(b) sec²θ
(c) cotθ
(d) – cotθ
Answer:
(d) – cotθ

Question 24.
\(\frac{d}{d x}\left(x^{1 / 3}\right)=\)

Answer:
(d) \(\frac{1}{3} x^{2 / 3}\)

Question 25.
∫ sin 2x dx =
(a) K + 2 cos2x
(b) \(\frac{\cos 2 x}{2}+K\)
(c) \(K-\frac{\cos 2 x}{2}\)
(d) \(K-\frac{\cos 2 x}{3}\)
Answer:
(c) \(K-\frac{\cos 2 x}{2}\)

Question 26.
∫x⁴dx =
(a) K + x⁵
(b) \(K+\frac{x^{4}}{5}\)
(c) \(K+\frac{x^{5}}{5}\)
(d) \(K+\frac{x^{5}}{4}\)
Answer:
(c) \(K+\frac{x^{5}}{5}\)

Question 27.
∫e^3x dx =
(a) e^3x + K
(b) K + 3e^3x
(c) \(\frac{e^{3 x}}{3}+K\)
(d) \(\frac{e^{3 x}}{4}+K\)
Answer:
(c) \(\frac{e^{3 x}}{3}+K\)

Question 28.
\(\int \frac{3}{x} d x=\)
(a) K + 3x²
(b) \(K-\frac{3}{x^{2}}\)
(c) 3x + K
(d) K + 3 log|x|
Answer:
(d) K + 3 log|x|

Question 29.
∫3dx =
(a) 3 + K
(b) x + K
(c) 3x + K
(d) 3K
Answer:
(c) 3x + K

Question 30.
∫√x.dx =

Answer:
(c) \(\frac{2}{3} x^{3 / 2}+K\)

Question 31.
\(\int_{0}^{\pi / 2} \sin x d x=\)
(a) 0
(b) 1
(c) -1
(d) \(\frac{\pi}{2}\)
Answer:
(b) 1

Question 32.
\(\int_{0}^{1} e^{x} d x=\)
(a) e
(b) e + 1
(c) e – 1
(d) 2e
Answer:
(c) e – 1

Question 33.
The solution of the equation \(\frac{d x}{x}=\frac{d y}{y}\) is
(a) x = Ky
(b) xy = K
(c) x + y = K
(d) x – y = K
Answer:
(a) x = Ky

Question 34.
The solution of the differential equation cosx dx + cosy dy = 0 is
(a) sinx + cosy = K
(b) sinx + siny = K
(c) cosx + cosy = K
(d) None of these
Answer:
(b) sinx + siny = K

Question 35.
The solution of e^xdx + e^ydy = 0
(a) e^x + e^y= K
(b) e^x – e^y = K
(c) e^x+y = K
(d) None of these
Answer:
(a) e^x + e^y= K

Question 36.
The integrating factor of the linear differential equation \(\frac{d y}{d x}+x y=x^{3}\) is
(a) e^x
(b) \(e^{\frac{x^{2}}{2}}\)
(c) x
(d) None of these
Answre:
(b) \(e^{\frac{x^{2}}{2}}\)

Question 37.
∫ logdx =
(a) x log x – x + K
(b) x log x + x + K
(c) \(\frac{1}{x}+K\)
(d) \(\frac{1}{2}(\log x)^{2}+K\)
Answer:
(a) x log x – x + K

Question 38.
\(\int \frac{d x}{1+x^{2}}=\)
(a) tan^-1 x + K
(b) sin^-1 x + K
(c) cos^-1 x + K
(d) cot^-1 x + K
Answer:
(a) tan^-1 x + K

Question 39.
\(\overrightarrow{| \vec{i}} |=\)
(a) 0
(b) 1
(c) 2
(d) 3
Answer:
(b) 1

Question 40.
\(\vec{i} \cdot \vec{i}=\)
(a) 0
(b) 1
(c) \(\vec{j}\)
(d) \(\vec{k}\)
Answer:
(b) 1

Question 41.
\(\vec{i} \times \vec{i}=\)
(a) \(\vec{i}\)
(b) \(\vec{0}\)
(c) \(\vec{j}\)
(d) \(\vec{k}\)
Answer:
(b) \(\vec{0}\)

Question 42.
If O is the origin and the position vector of a point(2,3,4) then \(\overrightarrow{\mathrm{OA}}=\)

Answer:
(b) \(2 \vec{i}+3 \vec{j}+3 \vec{k}\)

Question 43.
\(\overrightarrow{| i}+2 \vec{j}+3 \vec{K} |=\)
(a) 14
(b) 6
(c) 1
(d) √14
Answer:
(d) √14

Question 44.
\((2 \vec{i}-3 \vec{j}+4 \vec{k}) \cdot(3 \vec{i}+4 \vec{j}-5 \vec{k})=\)
(a) 14
(b) -14
(c) 26
(d) -26
Answer:
(d) -26

Question 45.
The direction cosines of the y-axis are
(a) 0, 0, 0
(b) 1, 0, 0
(c) 0, 1, 0
(d) 0, 0, 1
Answer:
(c) 0, 1, 0

Question 46.
The condition for two lines having direction cosines I₁ m₁,n₁ and I₂, m₂, n₂ being parallel is
(a) l₁l₂ + m₁m₂ + n₁n₂ = 0
(b) \(\frac{I_{1}}{I_{2}}+\frac{m_{1}}{m_{2}}+\frac{n_{1}}{n_{2}}=0\)
(c) \(\frac{I_{1}}{I_{2}}=\frac{m_{1}}{m_{2}}=\frac{n_{1}}{n_{2}}\)
(d) None of these
Answer:
(c) \(\frac{I_{1}}{I_{2}}=\frac{m_{1}}{m_{2}}=\frac{n_{1}}{n_{2}}\)

Question 47.
The equation of a plane parallel to the plane x + 2y + 3z + 5 = 0 is
(a) x + 2y + 3z + 5 = 0
(b) x – 2y + 3z + 5 = 0
(c) x + 2y – 3z + 5 = 0
(d) None of these
Answer:
(d) None of these

Question 48.
The equation of a plane parallel to yz-plane is
(a) x + K
(b) y = K
(c) z = K
(d) None of these
Answer:
(a) x + K

Question 49.
If A and B be two arbitrary events where A ≠ φ then P (A∩B) =
(a) P (A). P (B/A)
(b) P (A) + P (B/A)
(c) P (A) – P (B/A)
(d) None of these
Answer:
(a) P (A). P (B/A)

Question 50.
The function in a linear programming problem whose maximum or minimum value has to be determined is called
(a) Objective function
(b) Constraint
(c) Both (a) and (b)
(d) None of these
Answer:
(a) Objective function

Non-Objective Type Questions

Short Answer Type Questions

Question No. 1 to 25 are short answer type questions. Each question of this category carries 2 marks. Answer any 15 questions. (15 x 2 = 30)

Question 1.
Examine whether the function f: R → R is one-one or many-one where f (x) = | x |, x ∈ R
Answer:
We have f(-1) = |- 1| = 1 and f(-1) = | 1 | = 1
Thus two different elements in R have the same Image,
∴ f is not one-one function, f is many one function.

Question 2.
Prove that 2 \(\tan ^{-1} \frac{1}{5}+\tan ^{-1} \frac{1}{4}=\tan ^{-1} \frac{32}{43}\)
Answer:

Question 3.
Solve for x : cot^-1 x + sin ^-1\(\frac{1}{\sqrt{5}}\) = \(\frac{\pi}{4}\)
Answer:

Question 4.
Find the value of x from the following
\(\left[\begin{array}{cc}
2 x-y & 5 \\
3 & y
\end{array}\right]=\left[\begin{array}{cc}
6 & 5 \\
3 & -2
\end{array}\right]\)
Answer:
Given that \(\left[\begin{array}{cc}
2 x-y & 5 \\
3 & y
\end{array}\right]=\left[\begin{array}{cc}
6 & 5 \\
3 & -2
\end{array}\right]\)
∴ 2x – y = 6 ………..(1)
y = -2………..(2)
from (i) 2x + 2 = 6 ⇒ 2x = 4. ∴ x = 2
∴x = 2, y = 2

Question 5.
Evaluate:
\(\left|\begin{array}{ccc}
16 & 9 & 7 \\
23 & 16 & 7 \\
32 & 19 & 13
\end{array}\right|\)
Answer:

Question 6.
When Evaluate x : \(\left|\begin{array}{ll}
x & 4 \\
2 & 2 x
\end{array}\right|=0\)
Answer:
Given that \(\left|\begin{array}{ll}
x & 4 \\
2 & 2 x
\end{array}\right|=0\)
⇒ 2x² – 8 = 0
⇒ 2x² = 8
⇒ x² = 4
∴ x = ±2

Question 7.
If A = \(\left[\begin{array}{c}
2 \\
-4 \\
3
\end{array}\right]\) and B = [ 2 3 4] then find B’A’
Answer:

Question 8.
If y + x = sin (y +x) then find dy/dx
Answer:

Question 9.
If \(y=\log \left(x^{2} \sqrt{x^{2}+1}\right)\) then find \(\frac{d y}{d x}\)
Answer:

Question 10.
If x = a cosθ, y = b sinθ, then find dy/dx
Answer:
Given that x = acosθ
D.W.R. to θ \(\frac{d x}{d \theta}\) = -asinθ…(i)
and y = bsinθ
D.w.r. to θ ; \(\frac{d y}{d \theta}\) = bcosθ …(ii)
\(\frac{(\mathrm{ii})}{(\mathrm{i})} \frac{d y}{d x}=-\frac{b}{a} \cot \theta\)

Question 11.
Integrate ∫ (sin x +cos x)²dx.
Answer:
Let I = ∫ (sin x + cos x)² dx
= ∫ (sin²x + cos²x + 2sinx-cosx)dlv
= ∫ (l + sin 2x)clx = ∫ dx + ∫ sin 2x dx
= \(x-\frac{\cos 2 x}{2}+c\)

Question 12.
Evaluate: \(\int_{0}^{\pi / 2} \frac{d x}{1+\sin x}\)
Answer:

Question 13.
Evaluate : \(\int_{0}^{\pi / 2} \frac{\sin x d x}{\sin x+\cos x}\)
Answer:

Question 14.
Solve \(\frac{d y}{d x}\) – y tanx =-ysec²x.
Answer:
Given differentia] Equation is \(\frac{d y}{d x}\) – y tanx =-ysec²x.
This is L.D.E. of the form \(\frac{d y}{d x}\) + Py = Q
Here p = – tan x Q = sec²x

∴ Solution of given diff. eqn. is
y x l.F.= ∫ Q-(lF)dx + C
⇒ ycosx = ∫sec²x.cosxdx + C
⇒ ycosx = ∫ secxdx + C
⇒ ycosx = log |secx + tanx| + C
This is requried solution of given diff. eqn.

Question 15.
Integrate : ∫x²e^xdx
Answer:
Let I = ∫x²e^xdx

Question 16.
Find the scalar product of \(\overrightarrow{5} \vec{i}+\vec{j}-3 \vec{k}\) and \(3 \vec{i}-\overrightarrow{4 j}+7 \vec{K}\)
Answer:
Let \(\vec{a}=5 \hat{l}+\hat{j}-3 \hat{k}\) and \(\vec{b}=3 \hat{\imath}-4 \hat{j}-7 \hat{k}\)
∴ \(\vec{a} \cdot \vec{b}\) = (5 x 3) + (1 x -4)÷(- 3 x 7)
15 – 4 – 21 = – 10

Question 17.
If \(\vec{a}=3 \vec{i}+4 \vec{j}-5 \vec{k}\) and b = \(7 \vec{i}-3 \vec{j}+6 \vec{K}\) then find \((\vec{a}+\vec{b}) \times(\vec{a}-\vec{b})\)
Answer:

Question 18.
Find the acute angle between two straight lines whose direction ratios are (1,1,0) and (2,1,2).
Answer:
Direction ratios of the first line are 1,1,0
∴Its direction cosines are

Direction ratios of the second line are 2,1,2
its direction cosines are

Question 19.
Find the values of p so that the lines \(\frac{11-x}{p}=\frac{3 y-3}{2}=\frac{17-z}{5}\) and
\(\frac{x-22}{3 p}=\frac{2 y-7}{27 p}=\frac{z-100}{6 / 5}\) are perpendicular to each other.
Answer:


⇒ -3p² + 9p – 6 = 0
⇒ 3p² – 9p + 6 = 0
⇒ p² – 3p + 2 = 0
⇒ p² – 2p – p + 2 = 0
⇒ p(p – 2) -1 (p – 2) =0
⇒ (p – 2) (p – 1) = 0
∴ p = 2, 1

Question 20.
Prove that the two planes, 3x – 4y + 5z = 0 and 2x – y – 2z = 5 are mutually perpendicular.
Answer:
Given equations of plane are 3x – 4y + 5z = 0 …(i)
and 2x-y-2z = 5 …(ii)
Here a₁= 3 b₁= – 4, c₁ = 5; a₂ = 2, b₂ = -1 c₂=- 2
a₁a₂ + b₁b₂ + c₁c₂; 6 + 4 – 10 = 0
Since product of Direction’ratios at two planes are zero, plane (i) & (ii) are perpendicular.

Question 21.
What is the probability of occurrence of a number greater than 2 if it is known that only even num¬bers can occur ?
Answer:
Let S = {1,2,3,4,5,6}; A = {2,4,6}
B= {3, 4, 5,6}

Question 22.
A person tosses a coin 3 times. Find the probability of occurrence of exactly one head.
Answer:
Let p = Probability of getting a head in one trial

Question 23.
If y = sin x + cosx, then find \(\frac{d^{2} y}{d x^{2}}\)
Answre:
Given that y = sinx + cosx; D.w.r. to x both sides
∴ \(\frac{d y}{d x}\) = cps x – sin x, Again D.w.r.to x both sides
⇒ \(\frac{d^{2} y}{d x^{2}}\) = – sin x – cosx (sinx + cosx)

Question 24.
Find the values of \(\left|\begin{array}{lll}
a & a^{2} & a^{3} \\
b & b^{2} & b^{3} \\
c & c^{2} & c^{3}
\end{array}\right|\)
Answer:

Question 25.
If A and B be two events and 2P (A) = P (B) = 6/13 and P (A/B) = 1/3, then find (P(A ∪ B)
Answer:

Long Answer Type Questions

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

Question 26.
If y = \(e^{x^{x}}\) then find \(\frac{d y}{d x}\)
Answer:

Question 27.
Prove that sinθ (1 + cosθ)has maximum value at θ = \(\frac{\pi}{3}\)
Answer:
Let y = sinθ(1 + cosθ)
D .w.r. to 0 both sides

Question 28.
Evaluate : \(\int_{0}^{\pi} \frac{x}{1+\sin x} d x\)
Answer:

Question 29.
Solve: (x² + y2)\(\frac{d y}{d x}\) = 2xy
Answer:
Given differential equ. is (x² + y2)\(\frac{d y}{d x}\) = 2xy

This is Homogeneons diff. equation put y = vx

Question 30.
Maximize : Z = 50x + 15y
subject to : 5A + y ≤ 5, x + y ≤ 3 and x, y ≥ 0
Answer:
Its corresponding equation
5x + y = 5 …… (i)
x + y = 3 ……..(ii)

Question 31.
A speaks the truth in 75% casses and B in 80% of the cases. In what percentage of cases are they likely to contradict each other in stating the same fact ?
Answer:
Let E = The Event of A speaking the truth and F = The Event of B speaking the truth.
Then P(E) = \(\frac{75}{100}=\frac{3}{4}\) and P(F) = \(\frac{80}{100}=\frac{4}{5}\)
Required probability P(A & B contradicting each other)
= P(EF̄) or ĒF) = P(EF̄+ĒF)= P(E)- P(F̄) + P(Ē).P(F)
= P(E) .[1 – P(F)]+[1 – P(E). P(F)]
∴ A &.B are likely to contradict each other in 35% cases.

Question 32.
Find the acute angle between the straight line \(\frac{x}{1}=\frac{y}{3}=\frac{z}{0}\) and plane 2x + y = 5
Answer:
Given that \(\frac{x}{1}=\frac{y}{3}=\frac{z}{0}\) and 2x + y = 5
Here a₁, b₁, c₁ & a₂ = 2, b₂= 1, c₂ = 0
∴ Acute angle between the given line and plane is

Question 33.
Factorize. \(\left|\begin{array}{ccc}
(b+c)^{2} & a^{2} & a^{2} \\
b^{2} & (c+a)^{2} & b^{2} \\
c^{2} & c^{2} & (a+b)^{2}
\end{array}\right|\)
Answer:

Bihar Board 12th Economics Model Papers

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

Time : 3 Hour 15 Min
Full Marks : 100

Instructions

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

Objective Type Questions

Questions no. 1 to 50 have four options provided out of which only one is correct. You have to mark, your selected option, on the OMR-Sheet. Each question carries 1 (one) marks.

Question 1.
Production Possibility curve is :
(a) Concave to the axis
(b) Convex to the axis
(c) Parallel to the axis
(d) Vertical to the axis
Answer:
(a) Concave to the axis

Question 2.
Which one is the limitation of Macro Economics ?
(a) Collective Economic
(b) Paradox
(c) Both A and B
(d) None of these
Answer:
(c) Both A and B

Question 3.
How we calculate marginal utility ?
(a) \(\frac { ΔMU }{ ΔQ }\)
(b) \(\frac { ΔTU }{ ΔQ }\)
(c) \(\frac { ΔQ }{ ΔTU }\)
(d) \(\frac { ΔQ }{ ΔMU }\)
Answer:
(b) \(\frac { ΔTU }{ ΔQ }\)

Question 4.
Who propounded the ordial utility theory ?
(a) Marshall
(b) Pigou
(c) Recardo
(d) Hicks & Allen
Answer:
(d) Hicks & Allen

Question 5.
The quantity of goods which the seller is ready to sell in a market at fixed price and time is called.
(a) Supply
(b) Demand
(c) Elasticity of supply
(d) Elasticity of Demand
Answer:
(a) Supply

Question 6.
Which is a reason of change in demand ?
(a) Change of consumer’s income
(b) Change in price of related goods
(c) Population Increase
(d) All of these
Answer:
(d) All of these

Question 7.
For Giffin goods, price elasticity of demand is :
(a) Negative
(b) Positive
(c) Zero
(d) None of these
Answer:
(b) Positive

Question 8.
Production function is expressed as :
(a) QX = PX
(b) QX = DX
(c) QX = f (A,B,C,D)
(d) None of these
Answer:
(c) QX = f (A,B,C,D)

Question 9.
Which of the following is not fixed cost ?
(a) Cost of raw materials
(b) Rent of the factory
(c) Interest
(d) Insurance Premium
Answer:
(a) Cost of raw materials

Question 10.
Which of the following is true ?
(a) TVC = TC – TFC
(b) TC = TVC – TFC
(c) TFC = TVC – TC
(d) TC = TVC × TFC
Answer:
(a) TVC = TC – TFC

Question 11.
In which market MR may become zero or negative ?
(a) Monopoly
(b) Monopolistic competition
(c) Both A and B
(d) Perfect competition
Answer:
(c) Both A and B

Question 12.
In perfect competition :
(a) AR = MR
(b) AR > MR
(c) AR < MR
(d) AR + AC = MR
Answer:
(a) AR = MR

Question 13.
The basic condition of a firm’s equillibrium is :
(a) MR = AR
(b) MC > MR
(c) MR < TR
(d) AC = AR
Answer:
(b) MC > MR

Question 14.
If the price of goods rises by 20% and supply increases by 40%, then the supply of such goods will be :
(a) Elastic
(b) Inelastic
(c) Highly Elastic
(d) Perfectly Elastic
Answer:
(d) Perfectly Elastic

Question 15.
Which one of the following is true for monopoly.
(a) Firm is price-maker
(b) Demand curve slops downward
(c) Price discrimination Possibility arises
(d) All of the above
Answer:
(d) All of the above

Question 16.
Who gave the concept of ‘Time Element’ in price determination process ?
(a) Ricardo
(b) Walras
(c) Marshall
(d) J.K. Mehta
Answer:
(c) Marshall

Question 17.
Which is the component of factor price determination ?
(a) Rent
(b) Wages
(c) Interest
(d) All of the above
Answer:
(d) All of the above

Question 18.
The elasticity of a straight line supply curve originating from the centre of origin is
(a) Less than unit
(b) Greater than unit
(c) Equal to unit
(d) Equal to Zero
Answer:
(c) Equal to unit

Question 19.
The alternative name of opportunity cost is :
(a) Equilibrium Price
(b) Economic Cost
(c) Marginal Cost
(d) Average Cost
Answer:
(b) Economic Cost

Question 20.
What happens when production is shut down ?
(a) Variable costs become zero
(b) Fixed costs increases
(c) Variable costs decline
(d) Fixed costs become zero
Answer:
(a) Variable costs become zero

Question 21.
A curve which rises first and starts declining after that is called :
(a) APP
(b) MPP
(c) TPP
(d) All these
Answer:
(d) All these

Question 22.
An active factor of production is :
(a) Capital
(b) Labour
(c) Land
(d) None of these
Answer:
(c) Land

Question 23.
Which of the following is the main reason of operating the Law of Dimishing Returns ?
(a) Scarcity of factors
(b) Imperfect Substitution between Factors
(c) Both A and B
(d) None of these
Answer:
(c) Both A and B

Question 24.
Average variable costs is :
(a) TVC × Q
(b) TVC + Q
(c) TVC – Q
(d) TVC ÷ Q
Answer:
(d) TVC ÷ Q

Question 25.
“Supply creates its own demand”. Who propounded this law ?
(a) J.B. Say
(b) J.S. Mill
(c) Keynes
(d) Ricardo
Answer:
(a) J.B. Say

Question 26.
With increase in investment, MEC :
(a) Rises
(b) Falls
(c) Remains Constant
(d) None of these
Answer:
(b) Falls

Question 27.
Increase in aggregate demand of equilibrium level of income and employment causes increase in :
(a) Employment
(b) Production
(c) Income
(d) All of the above
Answer:
(d) All of the above

Question 28.
Which one is correct ?
(a) A.K = \(\frac { 1 }{ MPc }\)
(b) B.K = \(\frac { 1 }{ MPc }\)
(c) C.K = \(\frac { 1 }{ 1-MPc }\)
(d) D.K = \(\frac { 1 }{ 1+MPs }\)
Answer:
(b) B.K = \(\frac { 1 }{ MPc }\)

Question 30.
Which of the following is included in secondary sectors ?
(a) Insurance
(b) banking
(c) Trade
(d) Investment
Answer:
(d) Investment

Question 31.
Net national income at Factor cost is called :
(a) National Income
(b) Gross Investment
(c) Domestic Income
(d) None of these
Answer:
(a) National Income

Question 32.
The market value of all final goods and services produced in an economy over a year is called :
(a) Gross National Product
(b) National Income
(c) Gross Domestic Product
(d) Net National Product
Answer:
(c) Gross Domestic Product

Question 33.
Which service is included in Tertiary Sector ?
(a) Mining
(b) Communication
(c) Construction
(d) Animal Husbandry
Answer:
(b) Communication

Question 34.
GNPMP = ?
(a) GNP_MP – Depreciation
(b) GNP_MP + Net Factor Income from abroad
(c) GNP + Subsidy
(d) None of the above
Answer:
(b) GNPMP + Net Factor Income from abroad

Question 35.
Which of the following is correct ?
(a) Disposable Income = Personal Income – Direct Taxes
(b) Disposable Income = Private Income – Direct Taxes
(c) Disposal Income = Personal Income – Indirect Taxes.
(d) Disposal Income = Private Income – Indirect Tases
Answer:
(a) Disposable Income = Personal Income – Direct Taxes

Question 36.
Which Objectives government attempts to obtain by Budget ?
(a) To Promote Economic Development
(b) Balanced Regional Development
(c) Redistribution of Income and Wealth
(d) All the above
Answer:
(d) All the above

Question 37.
Which of the following Budget is suitable for Developing Economy ?
(a) balanced Budget
(b) Surplus Budget
(c) Deficit Budget
(d) None of these
Answer:
(c) Deficit Budget

Question 38.
Foreign exchange is determined by :
(a) Government
(b) Bargaining
(c) World Bank
(d) Demand and supply forces
Answer:
(d) Demand and supply forces

Question 39.
“Budget is a preliminary approval Plan of Public revenue and expenditure”. Who said?
(a) Rane stourn
(b) Findlay Shirras
(c) Taylor
(d) Dalton
Answer:
(d) Dalton

Question 40.
“Money is what mobey does” who said it ?
(a) Hartley Withers
(b) Hawtrey
(c) Prof Thomas
(d) Keynes
Answer:
(a) Hartley Withers

Question 41.
The function of money is
(a) Medium of exchange
(b) Measure of value
(c) Store of value
(d) All of the above
Answer:
(d) All of the above

Question 42.
What is Central Bank of India ?
(a) Central Bank
(b) Commercial Bank
(c) Private Bank
(d) Co-operative Bank
Answer:
(b) Commercial Bank

Question 43.
Who regulates money supply ?
(a) Govt, of India
(b) Planning Commission
(c) Reserve Bank
(d) Commmercial Bank
Answer:
(b) Planning Commission

Question 44.
Who is the Banker’s of the Bank ?
(a) Reserve Bank of India
(b) State Bank of India
(c) Unit Trust of India
(d) None of the above
Answer:
(a) Reserve Bank of India

Question 45.
In which year Banking Ombudsman Scheme was announced ?
(a) 1990
(b) 1955
(c) 1977
(d) 1988
Answer:
(b) 1955

Question 46.
Which type of currency is issued by the central Bank ?
(a) Currency
(b) Credit Money
(c) Coins
(d) All the above
Answer:
(a) Currency

Question 47.
Which items are included in Balance of Payments?
(a) Visible items
(b) Invisible items
(c) Capital Transfer
(d) All the above
Answer:
(d) All the above

Question 48.
Balance ot Trade means
(a) Capital Transaction
(b) Import Export of goods
(c) Total Debit and Credit
(d) All of the above
Answer:
(b) Import Export of goods

Question 49.
The meaningt of Spot Market relates to foreign exchange is ?
(a) Current Transactions
(b) Transactions of mid-period
(c) Transactions of Long Term
(d) None of these
Answer:
(a) Current Transactions

Question 50.
The Hybrid systems of exchange rate related to
(a) Wider Bands
(b) Crawing peg
(c) Managed Floating
(d) All of them
Answer:
(d) All of them

Non-Objective Type Questions

Short Answer Type Questions

Question no. 1 to 25 are Short answer type questions. Answer any 15 them in 50 words. Each question carries 2 marks. (15 x 2 = 30)

Question 1.
What do you understand by Micro Economics ?
Answer:
Small units of an economy are included in micro economics e.g. one consumer, one producer, one firm, one industry etc. In other words, individual units are studied in micro economics.

According to K.E. Boulding, “Micro economics may be defind as that branch of analysis, which studies the economics behaviour of the individual unit, may be a person, a particular house-hold or a particular firm. It is a study of one particular unit rather than all the units combined together,”

Question 2.
Write two main components of Macro Economics ?
Answer:
The term Macro in English shas its origin in the Greek term Macros which means large. In the context of macro economics “large” means economy as a whole. Thus, macro economic is defined as that branch of economics which studies economic activies at the level of an economy as a whole.

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

Question 3.
Distinguish between utility and total utility. Ans. Demand schedulers that schedule which, other things, remaining constant, expresses the relation between different quantities of the commodity demanded at different prices. The table relating to price and quantity demanded is called the demand schedule.
Demand schedule is of two types :

• Individual demand schedule
• Market demand schedule.

1. A more and more units of a commodity are consumed the marginal utility derived from each successive unit goes on diminishing. But the total utility increases up a limit.
2. Marginal utility of the first four units, being positive the total utility goes on increasing thus, as long as the marginal utility of the commodity remains positive, total utility goes on increasing.
3. Marginal utility of the sixth unit is negative (-2). As a result of it, total utility of six units of the commodity falls from 20 to to 1 units.
   Thus,
   1. When MU diminishes, TU tends to increase at a diminishing rate
   2. When MU is zero, Tu is maximum
   3. When MU is negative, TU starts diminishing.

Question 4.
What is indifference curve ?
Ans. Indifference curve explains the consumer’s behaviour related with the combination of two goods and this consumer’s behaviour is explained with the help of “Indifference schedule or Indifference set.” various combinations of two goods giving equal satisfactions to the consumer become the component of ‘Indifference schedule’, When indifference schedule is represented on a graph paper, we get indifference curve.

In the words of watson “An indifference schedule is the lists of combination of two commodities, the list being so arrange that a consumer is indifferent to the combinations preferring more of any other”.

Question 5.
What are the exceptions of law of Demand ?
Answer:
There are following to the Law of Demand.

1. Expected rise in future price
2. Prestigious Goods
3. Ignorance of consumer
4. Giffin’s Paradox,

Question 6.
Explain any two factors that affect price elasticity.
Answer:
Factors affecting elasticity of demand are discussed below.

1. Substitutes : When substitute of any goods is available, then deamnd elasticity of such goods is highly elastic because when price of these goods increases, subsutities are used in place of it. In the same way on decrease in price of these goods, use of substitutes decrease. Tea, coffee, gas, sugar etc. are examples of subsitutes.
2. Alternative uses : When goods could be used in only one way, its demand will be elastsic and when it would be used in many ways, its demand will be elastic eg. coal has so many used-it can be used industries houses ralways etc. Demand of coal for railways in elastic but for house purpose, its cheeper alternative goods like wood cooking gas etc. could be used in place of it.

Question 7.
What do you understand by Production Function ?
Answer:
A Production expresses the technical relationship between input and output of a firm. It tells us about the maximum quantity of output that can be produced with any given quantities of inputs. If there are two factor inputs, labour (L) and capital (K), then production function can be written as :
Q = f (L, K) where
Q = Quantity of output
L = Units of labour
K = Units of capital
It may be pointed here that both the inputs are necessary for the production. If any of the inputs is zero, there will be no production with both inputs and output will also be zero, As we increase the amount of any one input, output increases.

Question 8.
What is difference between Explicit Cost and Implicit Cost ?
Answer:
Explicit cost: Explicit costs refer to the actual money outlay of the firm to buy or wire the productive resources, it needs in the process of proudction.
Implicit Costs : Implicit costs are payments which are not directly or actually paid out by the firm as no contractual disbursement is fixed for them. It includes the prices of such services and factors which are used in production process but are not directly paid.

Question 9.
Why does a firm attain maximum Profit When MR = MC ?
Answer:
MC stands for marginal cost incurred by a firm when its production raises by one unit. If the marginal cost is smaller than the marginal revenue (MR), then it is profitable for the firm to produce on extra Unit of output.

Question 10.
What are the different types of supply elastiicity ?
Answer:
Following are the types of elasticity supply.

1. Perfectly Elastic Supply (e_V = ∞)
2. Greater than unitary Elastic supply (e_s> 1)
3. Unitary Elastic Supply (e_s = 1)
4. Inelastic Supply (e_s < 1)
5. Perfectly Inelastic supply (e_s = 0)

Question 11.
Write three main features of monopoly market.
Answer:
Features of monopoly are as under-

1. One seller and large number of buyers : Under monopoly, there should be a single producer of a commodity. He may be alone or there may be a group of partner or a joint stock company. Thus, there is only one firm under monopoly. But the buyers of the product are in large number.
2. Restrictions on the entry of the new firms : Under monopoly, there are some estrictions on the entry of new firms into monopoly industry.
3. No close substitutes : A monopoly firm produces, a community that has close substitutes.
4. Full control over price : A monopolist has full control over its price. A monopolist thus, is a price maker. He can fix whatever price he wishes to fix for his product.
5. Possibility of price discrimination : A
   monopolist charges different prices from different consumers. It is called price descrimination. It refers to the practice by a seller of charging different prices from different buyers for the same good.

Question 12.
Explain the Circular Flow of Income.
Answer:
Production gives birth to income, income to consumption, consumption to ependiture and again expenditure to income and production. Thus, circular flow of income earning economic activities takes place in the economy.
According to hipster, “The circular flow of income is the flow of payment and receipt between domestic firms and domestic households.”

Hence, the circular flow of income refers to flow of money income or the flow of goods an services across different sectors of the economy in a circular form.

Question 13.
What are the uses of National Income Accounting ?
Answer:
The information collected through nation income accounting can be used for a variety of purposes, such as assessing the current standard of living or the distribution of income within a population. Additionally, national income accounting provides a method for comparing activities within different sectors in an economy, as well an changes within those sectors over time. A thorough anlysis can assist in determining overall economic stability within a nation.

Question 14.
What is the relationship between Gross Domestic Product and Gross national Product.
Answer:
Distinction between GDP and GNP :

Question 16.
What is the difference between Standard money and Token Money ?
Answer:
The Indian rupee is a mixture of the standard money and the token money. Like standard money. It is unlimited legal tender, and like the token money, its face value is greater than its intrinsic value.

Question 17.
State the qualiity of good money.
Answer:
Following are the qualities of good money :

1. Utility : The metal with which coin is made, must bear the feature of utility. The metal must easily be accepted. Gold and silver are such metals which possess utility.
2. Port ability : The metal with which coin is made, can easily be tranferred from one place to antother. Gold and silver coins bear this feature also.
3. Durable : Money is saved by people and hence coin should be made of such metal which is durable from saving purpose.
4. Divisibility : Money metal should be divisible without my loss in its value. Gold and silver are such metals having the feature of divisibility.
5. Homogeneity : All units, of money should be homogeneous.
6. Economy : Minting cost’of coin should be minimum and the depreciation in the coin should be least.
7. Stability of Value : Money metal should be stable in value i.e. price fluctuation in the metal of coin should be minimum.
8. Liquidity : Money metal should be liquid in nature, metal should easily be converted into coins can again be converted into meta on easily.
9. Cognisibility : Metal should easily be indentified. Take coins on easily be traced out if metal of money is cognisible. Gold and silver are such metals having full cognisibility.

Question 18.
What is difference between cash credit and overdraft ?
Answer:
At the simplest level, overdraft and cash credit are just forms of borrowing. The institution allows you to withdrew funds that you do not have, usually in small amounts. The primary differences between these forms of borrowing is how they are secured and whether the money is lent out of a separate account.

Question 19.
State the types of Government Budget.
Answer:
Following are the types of Budget.

1. Balanced Budget.
2. Deficit Budget.
3. Surplus Budget.

Question 20.
Mention any two participants of the Foreign Exchange Market.
Answer:
Following are the two participants of foreign exchange market.

1. Central Banks.
2. Foreign Exchange Brokers.

Question 21.
What is unfavorable Balance of Payment.
Answer:
Unequal flow of money under an unfavorable balance of payments will reduce the country’s money supply and increase the exchange rate to currencies in other countries, causing issues with inflation, unemployment and production. Also called balance of payments deficit.

Question 22.
Explain the relationship between investment Multiplier and Marginal Propensity to consume.
Answer:
The Multiplier Effect. The marginal propensity to consume (MPC) is equal to AC/AY, where AC is change in consumption, and AY is change in income. If consumption increases by eighty cents for each additional dollar of income, them MPC is equal to 0.8/1 = 0.8.

Question 23.
When does demand become Inelastic ?
Answer:
Demand becomes inelastic when people by about the same amount whether the price drops or rises. That happens with things people must have, like gasoline. Drivers must purchase the same amount even when the price increases. Like wise, they don’t buy much more even if the price drops.

Question 24.
Explain two features of oligopoly ?
Answer:
Important features of oligopalistic market are :

1. Few sellers
2. Interdependence among sellers regarding policies about price and output determination.

Question 25.
What is meant by Revenue Deficit ?
Answer:
Revenue deficit is the excess of revenue expenditure over revenue receipts. Revenue receipts include both tax revenue and non-tax revenue. Similarly revenue expenditures also include both plan and non-plan expenditures on revenue account. Revenue dificit does not include items of capital receipts and capital expenditure.
[Revenue Deficit] = [Revenue Expenditur] – [Revenue Receipts]

Long Answer Type Questions

Question no. 26 to 33 are Long answer type questions. Answer any 4 of them in 100 words. Each question carries 5 marks. (5×4 = 20)

Question 26.
Explain the law of Demand. What are its assumptions ?
Answer:
Law of demand-Low of demand explains quantitative relation behueen price of goods and quantity demanded. Every consumer has a psychology to buy less amount or quantity of anything of high price and more quantity of low price, ceteris Paribus (others being equal), there is inrerse relationship between price of a goods and when price is low, demand is high.

Thus, P ∞\(\frac { 1 }{ Q }\) where, P = Price of commodity, Q = Quantity demanded
Assumptions of the law of demand-Law of demand is based on few assumptions. These assumptions are-

1. Consumer’s income should remain contant.
2. Consumer’s taste, nature, etc. should remain constant
3. Price of related goods should remain constant
4. Consumer remains unknown with new substitutes
5. There is no possibility of price change in future.

Question 27.
Explain the factors determining elasticity of demand.
Answer:
Factors affecting Elasticity of Demand :

1. Substitutes : When substitutes of any goods is available, then demand elasticity of such goods is highly elastic, because when price of these goods increases, substitutes are used in pace of it. In the same way, on decrease in price of these goods, use of substitutes decreases. Tea, coffee, sugar, etc. are examples of substitutes.
2. Alternative Uses : When goods could be used in only one way, its demand will be inelastic and when it would be used in many ways, its demand will be elastic. For example, coal has many uses-it can be used in railways, houses, industries, etc. Demand of coal for railway is inelastic but for house purpose, its demand is elastic as many cheaper alternative goods like wood, cooking gas etc. could be used in place of it.
3. Postponement of Consumption : If consumption of any goods can be postponed, its demand becomes elastic, e.g., a person has to woolen clothes. If due to some reason, price of woolens clothes increases, then consumer postpones the idea of buying another sweater in current year. In such a case, demand of woolen clothes for current year will be highly elastic.
4. Expenditure Amount: Goods on which large part of income is spent, are highly demand elastic and those goods on which small part of income is spent, their demand is generally inelastic. That is why, demand of television, radio, cycle, scooter, etc. is more elastic as compared to salt, wheat etc.
5. Income Level : Elasticity of demand for rich people is generally inelastic because increase in price level does not affect them severly while elasticity of demand for poor people is highly elastic because increase in prices affect their purchasing power a lot.

Question 28.
Explain the law of variabie proportion.
Answer:
According to Mrs. Joan Robinson, s”The law of diminishing returns, as it is usually, formulated states that with a fixed amount of any one factor of production, successive increase in the amount of others will after a point, yield a diminishing increment of output.”
Assumptions of the Law :

1. One factor of production is variable and others are fixed
2. All units of variable factor are homogeneous
3. There is no change in level of technique
4. Fixed factors are indivisible
5. Different factors of production are imperfect substitutes
6. Fixed factors are limited and scarce.

Explaination of the Law or Three Stages of Production : Three stages of variable porportion have been depicted in the table :

Above table explains all the three stages of variable proportion :

(i) Stage of Increasing Returns : In the first stage, as the units of variable factor are increased with fixed factor, increased production takes place because as we increase units of variable factor, optimum utilisation of fixed factor becomes possible. Thereby, total production, average production and marginal production all increase in the beginning of stage of production.

There are two parts of the first stage. In the first part, MP and AP both increase. At third unit of variable factor, Mp is maximum. At fourth unit, MP decreases but AP continues to increase. In the beginning, both AP and MP increase but in second part of the stage, AP increases, although MP continues to decrease. The mid-point between first and second stage of production is called ‘Point of Inflexion’. First stage ends at the point where AP is maximum. In the first stage, AP in increasing continuously from starting till end. That is why, this stage is also called stage of
increasiong Average Return or Increasing Return Stage.

(ii) Stage of Diminishing Returns : In the second stage, AP and MP both are decreasing. This stage ends at the point, where MP becomes zero. In this stage, TP increases at a decreasing rate because MP is decreasing but remains positive.
In this stage, AP continues to decline and so, this stage is also called ‘Stage of Decreasing Average Product’.

(iii) Stage of Negative Returns : In this third stage of production, MP becomes negative or less than zero. Due to negative Marginal Product. Total Product (i.e., TP) starts declining. Due to decreasing TP and negative MP, this stage is also called ‘Stage of Negative Returns’.
Diagrammatic Representation
Stage I : Till ON quantity of variable factor.
Stage II: In between NS quantity of variable factor.
Stage III : After OS quantity of variable factor.

In above fig. Law of Variable Proportion has been represented. Other factors being fixed, change in quantity of one factor results in three different stages of production.

First Stage : Stage of Increasing Returns : This stage has been shown till ON quantity of variable factor. At the end of this stage, MP and AP become equal to each other (see point Q). In this stage, AP increases continuously and MP is positive and greater than AP as a result of which TP increases at the increasing rate. Reasons for increasing returns to a factor is that with less amount of variable factor in the beginning, optimum utilisation of fixed factors does not become possible.

As more and more units of variable factor are employed, intensive use of fixed factors becomes possible and production increases. In this way, additional units of variable factor increases efficiency of fixed factors. Fixed factors being indivisible cannot be used in lesser amount from technical point of view. So, they cannot be used with less amount of variable factor. Hence, more units of variable factor are used and it increases production. This is called increasing retunrs. In this stage, TP curve is shown point O to point K. OK can be divided into two parts or the first stage can be divided into two parts :

(a) Point O to Point F : TP is increasing with increasing rate because MP is continuously increasing till point P. Form point O to point F, TP is convex to X-axis.

(b) Point F to Point K : Total production increases but at a decresing rate because MP decreases but is positive (see point P to point Q). TP curve between point F to point K is concave to X-axis.

Point F on Total Product curve at which MP is maximum is called ‘Point of Inflexion’. After this point, total product increases at a decreasing rate.

Second Stage : Stage of Decreasing Returns : This stage has been shown on TP curve between point K and point T. In this stage, although TP increase but at a decreasing rate because both MP and AP i.e., marginal product and average product decreases. This stage, ends at the point, where MP is zero (Point S).

When MP is zero, then TP is maximum (see point T). This stage explains that if OS uits of variable factors are used, TP will be maximum. Reasons for decreasing returns an this stage are that fixed factors of production cannot be increased in short-run. When ON units of variable factors are.used with fixed factors, then MP decreases till zero level due to over utilisation of fixed fators and as a result of which internal diseconomies occur. In other words, extensive use of variable factors with fixed factors results in decline or decrease in MP.

Third Stage : Stage of Negative Returns : In this stage, Total Production (TP) starts decreasing after point T because at point T, marginal productivity of variable factors is zero. If after point S, an additional unit or marginal unit of variable factor is used, then marginal productivity of that additional unit becames negative and as a result TP starts declining. Therefore, this stage is called ‘Stage of Negative Returns’. In this stage, variable factors exceed fixed factors. This disbalanced or unequal ratio between the two, makes marginal productivity or variable factors negative.

Question 29.
Discuss the short-run cost curve with the help of diagram.
Answer:
Conceptually, in the short run, the quality of at least one input is fixed and the quantities of the other inputs can be varied. In tb. short-run period, factors, such as land and machi.iury, remain the same.

On the other hand factor such as labour and capital, vary with time. In the short run, the expansion is done by living more labour and in creasing capital. Following are the cost concepts that are taken into consideration in the short-run.

I. Total Fixed cost (T.F.C) : Refer to the cost that remain fixed in the short period. These costs do not change with the change in the level of output. Therefore, the slope of TFC curve is horizontal straight line.

II. Total variable cost (T.V.C) : Refers to the cost that change with the change in the level of production. If the output is zero, then variable cost is also zereo.

III. Total Cost (T.C.) : Involves the sum of TFC and TVC ss It can be calculated as follow total cost = TFC + TVC TC also changes with the changes in the level of output-on there is a change in TVC.

IV. Average Fixed Cost (AFC) : Refers to the per unit fixed costs of production. In other words, AFC inplies fixed cost of production divided by the quantity of output produced.
AFC = TFC/Output
TFC is constant on production increase, thus AFC falls.

V. Average Variable Cost (AVC) : Refer to the per unit variable cost of production. It implies organization’s variable costs divided by the quanity of output produced.
It is calculated as AVC = TVC/Outputty6

VI. Average Cost (AC) : Refers to the total costs- of production per unit of output.
AC is calculated as :
AC = TC/Output
AC = TC/Output
AC is equal to the sum of total of AFC and AVC

VII. Marginal Cost (MC): Refers to the addition to the total cost for producing on additional unit of product.
Marginal cost is calculated as :
MC = TC_N = TC_n-1
n = Number of units produced
It is calculated as :
MC = ATC/A Output

Question 30.
What is Perfect Competition ? Explain the characteristics of Perfect Competition.
Answer:
Perfect competition is that market situation in which a large number of buyers and sellers and found for homogeneous product single buyer or the seller are not capable of affecting the prevailing price and hence in a perfectly competition market, a single market price prevails for the commodity.
Features of Perfect Competition :

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

Question 31.
How the problems of double counting in computation of natonal income can be removed ?
Answer:
Meaning : Double counting means counting of the value of the same product (or ependiture) more than once. How ? According to output method, of calculating national income value of only final goods and services produced by all the production units of a country during a yera should be counted. In others words, value of intermediate goods which enter into final goods Ce.g. paper used in printing of books, raw cotton used in garments, wheat used in making breads, should not be taken into acount.

But in actual practice, while taking value of final goods, value of intermediate goods also gets included because every producer treats the commodity he sells as final irrespective of weather it is used as intermediate or final good. For instance, while taking value of final goods like cycles the value of tyres, tubes, frames, bells etc. (intermediate goods) used in manufacturing these cycles also gets included inadvertently.
In this way certain items are counted more than once resulting in over estimation of national product to the extent of the value of intermediate goods included. This is called the problem of double counting which means counting value of the same commodity more than once.

How to avoid Double Counting : Theoritically we may say that there may be two alternative ways of avoiding double counting namely
(i) final product approach
(ii) value added approach.
But in actual practice, double counting still occurs unintentionally- in final product approach because every producer treats the product he sells as final product though the same night have been used by the buyer as an intermediate product. Therefore, this problem is perfectly solved by value added method according to this method ‘instead of taking value of finai products, value added by eacb firm at each stage of production is included.

Clearly value added by all the four firms is Rs. 3500 comprising Rs. 1000 by A + Rs 500 by B + Rs. 700 by C + Rs: 1300 by D. There is no scope of double counting in this method. Thus to avoid double counting, the value added method also known as industry of origin method is used in computation of national income. It is worth mentioning that total value added is equal to value of final product.

Question 32.
What is Domestic Product ? How Gross Domestic Product is calculated ?
Answer:
Domestic product referss to the money value with in of all the final goods and services produced with in the domestic territory of a country, the following equation is used to calculate the Gross Domestic product (GDP): GDP = C +1 + G (X-M) or GDP = Private consumption + Gross isnvestment + government investment + government spending + (exports – imports).

It transforms the money value measure, nominal GDP, into an index for quantity of total output.

Question 33.
Explain main points of Keynesian theory of income and employment.
Answer:
According to Keynesian employment theory in short period; total production, i.e., national income in capitalist economy depends on the level of employment because in short period other factors of production such as capital, technique, etc., remain constant. Employment level depends on effective demand. That level of aggregate demand at which it becomes equal to aggregate supply is called effective demand.

Aggregate Demand : The total demand of goods and services in an economy is termed as ‘aggregate demands’ which is expressed in terms of total expenditure made in the economy. Thus, aggregate demand in an economy is measured in terms of total expenditure on goods and services.

In other words, aggregate demand refers to total expenditure that the residents of a country are ready to incur on the purchase of goods and services at given level of income.

Aggregate Demand = Consumption Expenditure + Investment Expenditure AD = C + I
Aggregate Supply : The concept of aggregate supply is related to the total supply of goods and services made available by all producers in the economy. It means that aggregate supply depends on the production made by producers.

A necessary condition of equilibrium (income level or employment level) in an economy is
Aggregate Demand = Aggregate Supply C+I=C+S

Classical viewpoint explains the income equilibrium level at full employment level, i.e., aggregate demand can equal aggregate supply only at a point of full employment.

Countrary to it, according to Keynesian viewpoint aggregate demand equals aggregate supply at the point before full employment level (i.e., taken place at underfull employment level). Aggregate demand has to be increased for increasing employment in the economy.

i.e. sin Keynesian viewpoint, under-full employment, equilibrium can be converted to full employment equilibrium only by increasing aggregate demand.

According to Keynes, “Under employment equilibrium is a situation in which aggregate demand (which is less than full employment aggregate demand) is equal to aggregate supply so that there is equilibrium but some resources remain unemployed.”

In this situation, factors are not fully employed and all laborers do not get employment. According to Keynes, under employment situation appears due to deficient aggregate demand but not due to deficiency of aggregate supply.
In above Fig. at ON 1 employment level, AD = AS but it is a situation of under-full employment. When aggregate demand AD increases to AD|, full employment level On is obtained.

Bihar Board 12th Biology Model Papers

Bihar Board 12th Biology Model Question Paper 2 in English Medium

Time : 3 Hours 15 Min
Total 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 indicate full marks.
3. While answering the questions, the candidate should adhere to the word limit as for 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 result will be treated as invalid.
7. 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
8. Use of any electronic device is prohibited.

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.
All tissue can be formed from
(a) Ectoderm
(b) Endoderm
(c) Mesoderm
(d) Stem cell
Answer:
(d) Stem cell

Question 2.
Astrogen and Progesterone are secreted by
(a) Ovary
(b) Testis
(c) Placenta
(d) All of the above
Answer:
(c) Placenta

Question 3.
Which one is not a part of anther wall?
(a) Endothecium
(b) Endothelium
(c) Tapetum
(d) All of the above
Answer:
(b) Endothelium

Question 4.
Which of the following is true fruit?
(a) Coconut
(b) Apple
(c) Pear
(d) Cashew
Answer:
(a) Coconut

Question 5.
Haploid chromosome number in dog is
(a) 23
(b) 39
(c) 19
(d) 4
Answer:
(b) 39

Question 6.
Which one does not show Oestrus cycle?
(a) Cow
(b) Sheep
(c) Monkey
(d) Dog
Answer:
(c) Monkey

Question 7.
Which one of the following is a major source of air pollution?
(a) Industries
(b) Automobiles
(c) Burning coals
(d) All of the above
Answer:
(d) All of the above

Question 8.
Bt cotton is resistant to
(a) Insects
(b) Weeds
(c) Salts
(d) None of the above
Answer:
(a) Insects

Question 9.
Lamarck was from
(a) India
(b) England
(c) France
(d) None of the above
Answer:
(c) France

Question 10.
Which among the following is a hereditary disease
(a) Haemophilia
(b) Diabetes
(c) Cretenism
(d) All of the above
Answer:
(a) Haemophilia

Question 11.
Which bacteria is helpful in the formation of curd from milk?
(a) Anabena
(b) Streptococcus
(c) Lactobacillus
(d) All of the above
Answer:
(c) Lactobacillus

Question 12.
The example of retrovirus is
(a) Plasmodium
(b) TMV
(c) HIV
(d) None of the above
Answer:
(c) HIV

Question 13.
Spermatogenesis produces
(a) Sperm
(b) Ova
(c) Zygote
(d) None of the above
Answer:
(a) Sperm

Question 14.
Humulin term is used for
(a) Digestive enzyme
(b) Antibiotic
(c) Chitin
(d) Human insulin
Answer:
(d) Human insulin

Question 15.
Pomato is a hybrid of
(a) Tomato and Cabbage
(b) Carrot and Radish
(c) Potato and Tomato
(d) None of the above
Answer:
(c) Potato and Tomato

Question 16.
The substance which causes a definite change in gene is called
(a) Mutagen
(b) Alkaloid
(c) Cytotoxin
(d) None of the above
Answer:
(a) Mutagen

Question 17.
Linkage was discovered by
(a) Muller
(b) Punnet
(c) Mendel
(d) Morgan
Answer:
(d) Morgan

Question 18.
A child with mother of A group and father of AB group will not have the following blood group
(a) A
(b) B
(c) AB
(d) O
Answer:
(d) O

Question 19.
The ratio 9 : 7 is produced due to
(a) Complementary genes
(b) Lethal genes
(c) Epistatic genes
(d) None of the above
Answer:
(a) Complementary genes

Question 20.
The exposure of X-ray enhances the frequency of
(a) Linkage
(b) Segregation
(c) Crossing over
(d) None of the above
Answer:
(c) Crossing over

Question 21.
Part of DNA which switch their position are called
(a) Exon
(b) Cistrons
(c) Transposons
(d) None of the above
Answer:
(c) Transposons

Question 22.
Nucleic Acids are polymers of
(a) Amino acid
(b) Nucleosides
(c) Nucleotides
(d) None of the above
Answer:
(c) Nucleotides

Question 23.
The lac operon consists of
(a) One structural gene
(b) Three structural gene
(c) Four structural gene
(d) None of the above
Answer:
(b) Three structural gene

Question 24.
The technique of DNA fingerprinting was initially developed by
(a) Alec Jeffreys
(b) Griffith
(c) Mirsky
(d) None of the above
Answer:
(a) Alec Jeffreys

Question 25.
In split genes, the coding sequences are called
(a) Exons
(b) Introns
(c) Cistrons
(d) Operons
Answer:
(a) Exons

Question 26.
Vermiform appendix is a
(a) connecting link
(b) vestigial organ
(c) homologous organ
(d) None of the above
Answer:
(b) vestigial organ

Question 27.
Use and disuse was proposed by
(a) Darwin
(b) Haeckel
(c) Lamarck
(d) None of the above
Answer:
(c) Lamarck

Question 28.
Modern man is called
(a) Neanderthals
(b) Ramapithecus
(c) Homosapiens
(d) None of the above
Answer:
(c) Homosapiens

Question 29.
Nervous system is influenced by
(a) Cocaine
(b) Heroine
(c) Hashish
(d) All of the above
Answer:
(d) All of the above

Question 30.
Pathogen of malaria is
(a) Aedes
(b) Wuchereria
(c) Anopheles
(d) Plasmodium
Answer:
(d) Plasmodium

Question 31.
The term ecology was coined by
(a) Odum
(b) Linnaeus
(c) Haeckel
(d) None of the above
Answer:
(c) Haeckel

Question 32.
Organisms which can inbreed with each other come under the same
(a) Kingdom
(b) Family
(c) Species
(d) Genus
Answer:
(c) Species

Question 33.
In a food chain, herbivores are
(a) Primary producers
(b) Primary consumers
(c) Secondary consumers
(d) None of the above
Answer:
(b) Primary consumers

Question 34.
Ovulation is induced by a hormone called
(a) FSH
(b) LH
(c) Both
(d) None of the above
Answer:
(b) LH

Question 35.
Bamboo species flower
(a) Only one in lifetime
(b) Every year
(c) Once in 12 years
(d) None of the above
Answer:
(c) Once in 12 years

Non-Objective Type Questions

Short Answer Type Questions

In this section, there are 18 short answer type question (each carryies 2 marks) out of which answers any ten (10) questions. (10 x 2 = 20)

Question 1.
Describe briefly a Technique of gel elecrophoresis.
Answer:
Gel electrophoresis is a technique of separating DNA fragments, formed by the action restriction endonucleases. The fragments of DNA are placed in typical agarose gel under an electric field. The DNA fragments move towards the anode as these fragments are negatively charged molecules. The DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel. The smaller the fragments size, the farther it moves.

The separated DNA fragments are stained with ethidium bromide followed by exposure to UV radiation. The DNA fragments are seen as orange coloured and are cut out from the agarose gel and extracted from the gel piece. This step is known as elocution. The DNA fragments purified in this way are used in construction recombinant of DNA by joining them with cloning vectors.

Question 2.
Where is Bee-keeping practiced ? What are the main points for successful bee-keeping ?
Answer:
The bee-keeping is practised in area where there are sufficient bee pastures of wild shrubs, fruit orchards and cultivated crops. Bee-hives can be kept in one’s courtyard, on the verandah of the house or even on the roof.
The main points for successful bee-keeping are :

1. Selection of suitable location for keeping bees.
2. Knowledge of the nature and habits of bees.
3. Catching and hiving of swarms.
4. Management of bee-hives during different seasons.
5. Handing and collection of honey and bees wax.

Question 3.
Write a short note on Haemophilia.
Answer:
It is sex linked recessive disease which is transmitted from unaffected carrier female to male progeny. In this disease a single protein is affected that is a part of the cascade of proteins involved in the clotting of blood. As a result of this a simple cut results into non stop bleeding. The heterozygous female (carrier) for haemophilia may transmit the disease to sons. The possibility of a female to become haemophilic is extremely rare because mother of such a female has to one atleast carrier and the father should be haemophilic. The family pedigree of Queen Victoria has a number of haemophilic descendents as she was a carrier of the disease.

Question 4.
Name one organ analogous to the wings of bird. Why are they both analogous ? Can you include the wing of bat also with them under the same category ? Give reasons.
Answer:
The wings of an insect are analogous to the wings of bird. They are analogous because both perform the same function but have the dissimilar structure and origin. The wings of an insect are modified outgrowth of the body without having bone where-as wings of birds are modified fore-limbs. The wings of a Vt cannot be put under the same category. The wings of a bat and birds are homologous organs as both are modified and perform the same function of flying.

Question 5.
How does sickle cell anaemia is caused ? What are its symptoms?
Answer:
Sickle cell anaemia is caused by the substitution of valine for glutamine at the sixth position in |3 chain of globin molecule of haemoglobin. The mutant haemoglobin molecule undergoes polymerization under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure. In this disease, red blood cells become elongated sickle like structure. It is autosomal disease due to recessive genes.

Symptoms-In this disease, red blood cells become elongated and curved under low oxygen tension. Individuals with this disease suffer attacks due to aggregation of red blood cells. These erythrocytes are destroyed more rapidly than the normal red blood cells leading to anaemia.

Question 6.
Define the term Biotechnology. Why has it become important lately?
Answer:
Biotechnology : It is the branch of micro-biological science which is concerned with the utilization of micro-organisms, plants and animal cells and their components to generate useful products and services in industrial processes.

Biotechnology has become very important because it gives us wide variety of products in immense qualities. Most of the industries for preparing alcohol, enzyme, antibiotic and vaccines etc. at large scale are using microbes. Through these products earlier used to prepare at home in meager amounts but biotechnology thas opened a new way with greater potentialities.

Question 7.
What is Adaptation? What type of adaptation is found in organisms of water?
Answer:
Adaptation is an attribute of the organism (morphological, physiological, behavioural) that enables the organisms to survive and reproduce in its habitat. Many adaptations have evolved over a long evolutionary time and are genetically fixed. In the absence of an external source of water, the Kangaroo rat in North American deserts is capable of meeting all its water requirement through the internal fat oxidation. It also has the ability to concentrate it urine so that minimum volume of water is used to remove excretory products.

Many desert plants have a thick cuticle on their leaf surfaces and have their stomata arranged in deep pits to minimise water loss through transpiration. Mammals from colder climates generally have shorter ears and limbs to minimise heat loss. This is called Allen’s Rule.

Question 8.
Explain main steps in plant breeding.
Answer:
Plant breeding as a technology has helped to increase yields to a very large extent. It is the purposeful manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant. Classical plant breeding involves crossing or hybridisation of pure lines, followed by artificial selection to produce plants with desirable traits of higher yield, nutrition and resistance to diseases. With advancements in genetics, molecular biology and tissue culture, plant breeding is now increasingly being carried out by using molecular genetic tools. Plant breeding programmes are carried out in a systematic way worldwide in government institutions and commercial companies.

Question 9.
Describe three advantages and three disadvantages of cross pollination in plants.
Answer:
Following are the three advantages of cross-pollination in plants:

• New hybrids of plants can be produced by this method.
• It introduces variations due to genetic recombination.
• The offsprings produce are better adapted to change in environment.

Three Disadvantages of Cross-pollination:

• There is enormous loss of pollen grains.
• Good characters can be diluted and undesirable characters will enter in the progeny.
• There is always a chance factor for it.

Question 10.
Distinguish between structural gene, regulatory gene and operator gene.
Answer:
Structural gene: This is a gene which has the information to code for amino acid sequence. It produces m-RNA to synthesize a specific polypeptide (enzymes) and it is regulated as a unit,by a single switch (operator).

Regulatory gene: It is a gene that produces repressor to inhibit the action of an operator gene and thus, turns off the operon. It also controls the rate of synthesis of the produces of other gene.

Operator gene: It is a gene which switches on or off the adjacent structural genes. When this gene is on, then the expression of structural genes occur to initiate the transcription and translation but in the off condition, no synthesis of polypeptide chain takes place.

Question 11.
Write a short note on ‘Adaptive Immunity’?
Answer:
Every antigen is processed by antigen-presenting cells like macrophages, B lymphocytes etc. The processed antigen is presented on the surface of these cells. A subgroup of T cells, called T-help cells, specifically interacts with the presented antigen and becomes activated. The activated T help cells then activate B cells and a sub-group of T cells called T cytotoxic cells in a specific manner. The activated B and T cytotoxic cells proliferate to produce clones. All the cells of a clone recognise the same antigen and eliminate it.

Question 12.
What is Biogas? Name the biomass and bacteria involved in the production of Biogas.
Answer:
Biogas is the mixture of gases (predominantly methane) produced during decay of biomass in the absence of oxygen. The biomass used in the production of biogas is animal dung, sewage, crop residues, vegetable wastes, water hyacinth, poultry droppings and wastes from agro-based industries. Methanogens (Methanobacterium) which grow anaerobically on cellulosic material produce large amount of methane along with CO₂ and H₂.

Question 13.
Expand ELISA. On what principle ELISA test is based?
Answer:
ELISA: means Enzymes Linked ImmunoSorbent Assay. This is a simple and versatile technique which is used most widely for the screening HIV and is based on the principle of Ag- Ab reaction.

Question 14.
How is rabies caused ? Write about its symptoms and control measures in brief.
Answer:
Rabies is caused by Iyssavirus type-1 which RNA containing virus. In man it is caused by the bite of a rabid dog. The disease is transmitted from one organism to other through the saliva which enters wound made by the bite of the animal.
Symptom: The virus stimulates nervous system and damage the cells of spinal cord and brain.
It causes high fever, severe pain. The victim develops fear from water (Hydrophobia)
Control:

• The patient should be isolated in a quiet room protected from external stimuli.
• A series of injections are advised to be injected.

Question 15.
What is Gene gun ? Give its utility.
Answer:
Gene gun: It is the new technology where vectorless direct gene transfer occurs in organisms. DNA coated into microscopic pellets is directly shot into target cells.

Utility: This technique is used to insert genes that promote tissue repair into cells near wounds, leading to a reduction of healing time.

Question 16.
Write the important symptoms of Down’s Syndrome.
Answer:
Down syndrome is also known as Trisomy. It is a genetic disorder caused by the presence of all or part of a third copy of chromosome -21 symptom.

• Developmental delays and physical and mental disabilities caused by genetic disorder.
• Flat face and short neck is present in child.

Question 17.
Write short notes on Global Warming.
Answer:
Global Warming is the phenomenon of increase in the global mean temperature caused by greenhouse gases. Due to global warming, there is average increase in temperature in the atmosphere.

Question 18.
What is transcription?
Answer:
The first step of protein syntheris is known as Transcription. During transcription step the instruction encoded in the DNA of the genes are transcribed into the nucleotide sequence code of a RNA. Because this RNA molecule causes the Protein Synthesis instruction in the word a ‘message’ from the gene to the ribosome. So, it is called mRNA.

Long Answer Type Questions

There are 6 long answers type question (each carrying 05 marks) out of which answers any three questions. (5 x 3 = 15)

Question 19.
Give an account of Anemophily.
Answer:
Anemophily is a mode of pollination or transfer of pollen grains from anther to stigma through the agency of wind. The flowers which are wind pollinated are called anemophilous. The anemophilous flowers are characterized by the following adaptations
(a) Flowers are small, colourless, inconspicuous, odourless and nectarless.
(b) Calyx and corolla are either reduced or absent.
(c) Filament of stamens are usually long and versatile.
(d) Pollen grains are small, light, dry, dusty and some times winged (e.g. pine).
(e) Pollen grains are infinite in number.
(f) Stigmas are hairy and branched.
(g) When flowers are unisexual, male flowers are more abundant than female flowers.
In bisexual flowers the stamens are generally numerous.
Examples of wind pollinated flowers are grasses, sugarcane, bamboo, maize etc.

Question 20.
Give an account of Recombinant DNA technology.
Answer:
rDNA technology:

1. DNA sequence is obtained from tissue culture.
2. Specific restriction endonuclease is selected from the specific bacteria.
3. Restriction endonuclease cuts specific DNA at the two ends.
4. Some restriction endonuclease cuts a matching DNA sequence from a plasmid.
5. Ligase enzyme which acts as a molecular glue joins the restriction fragment in the place vacated by the cut DNA segment of the plasmid. The plasmid DNA now contains foreign DNA and its DNA is called recombinant DNA (r.DNA)
6. Recombinant plasmids containing recombinant DNA are now injected into a host cell.
   This is done by electroporation.
7. Host bacterium divides to give multiple copies of recombinant DNA.
   

Question 21.
Define the following terms and give one example for each:
(a) Commensalism
(b) Parasitism
(c) Camouflage
(d) Mutualism
(e) Interspecific competition.
Answer:
(a) Commensalism: It is the type of interaction between two organisms where one is benefitted and the other is neither benefitted nor harmed.
Example: The sucker fish bears a sucker on the dorsal side of its head which helps it to attach itself to the body of the shark. It benefits the sucker fish to get free transportation as well as free food left behind by the Shark.

(b) Parasitism: It is a type of interaction between two organisms where one lives at the expense of other.
Here, one is benefitted (parasite) and the other is harmed (host).
Examples: Lice are parasite on humans and ticks on dogs.

(c) Camouflage: It is a type of protective mechanism in many animals where they assume different shapes and colours resembling to the background for deceiving the predators as well as for ensuring better survival.
Example: Stick insect (Carausins morosus) resemble like a dry stick and leaf insect (Phyllium) looks like a leaf. Similarly, Praying maints mimics the green foliage to protect themselves from the predators and prey.

(d) Mutualism: It is the relationship between two organisms where both are benefitted for food, shelter and substratum for attachment.
Example: The fungal symbiotic association with algae is called lichens. The algae manufacture the food and shares with fungi. On the other hand the fungus provides the structural converging the anchorage to the algae.

(e) Interspecific competition: It is the competition between the individuals of two different species occurring in a habitat. In shallow South American lakes, the visiting flamingoes and resident fishes have interspecific competition for their common food.

Question 22.
What are the various sources of water pollution? Name some important constituents of effluents.
Answer:
The water gets polluted by the following sources:
(a) Domestic Waste: The large quantities of municipal and household wastes are discharged into the water and cause water pollution.

(b) Industrial Wastes: The contamination of water occurs with the industrial wastes such as pulp mills, leather, tanneries, sugar and oil refinery, steel, textile and jute mills, petroleum and chemical fertilizer plants. These wastes contain very harmful substances like pesticides, bleaching powder etc. which largely affect the flora and fauna.

(c) Sewage: Disposal of sewage into rivers and lakes cause several undesirable effects. The sewage water contains several organic substances, human and animal excreta, food residues, cleaning agents, detergents and other wastes which provide nutrition to bacteria and fungi and consequently cause deoxygenation of water with the formation of algae blooms.

(d) Thermal Pollution: Release of large volumes of hot water into a stream can cause serious thermal pollution. This thermal pollution can upset the life-cycle and metabolic activities of many aquatic plants and fishes. Not only fish, but entire aquatic ecosystem is also affected by the thermal pollution and its toxic effect increases with further rise in temperature.

(e) Oils, Grease and Petroleum Products: These when discharged into water by accident or by design are extremely toxic and immediately affect the living organisms of the oceans.

(f) Radio Active Wastes: These wastes from atomic reactors and plants into rivers or streams can affect the aquatic plants and animals to a very great extent. They cause ionizations.

(g) Industrial Effluents: The increased quantity of dissolved salts in water like fluorine, alkalis, phenols, cyanides, mercury compounds, various metals, insecticides, pesticides and excess of fertilizers may produce harmful effect on living organisms. The consumption of mercury leads to crippling deformity called minamata disease.

Question 23.
What is pollution? Write an essay on air pollution.
Answer:
Pollution is an undesirable change in the physical, or biological characteristics of air, water and soil that may affect human life or any other organism. The World Health Organization defines air pollution as the presence of materials in the air in such concentration which are harmful to man and his environment. A number of ingradients find these are mostly gases, which rapidly spread over wide areas.

Sources of air pollution: The sources of air pollutions are very large and varied. These are:

(i) Industrial pollutants: The common air pollutants which are discharged by the industrial chimneys and power houses are S02, C02, H2S and hydrocarbon together with dust, smoke and girt.

(ii) Automobile exhausts: Automobiles run by petro and diesel produce carbon monoxide, nitrogen oxide and hydro-carbons. Hundred and thousands of tonnes of hydrocarbons and CO are emitted into air daily.

(iii) Ionizing radiations from radioactive substances: Ionizing radiations include ex, (3 particles and the gamma rays etc. These are produced by the atomic explosions and the testing of atomic weapons.

Air pollutants: The air pollutants have been separated into two categories directly from some identifiable sources.
These include: Sulphur compounds are SO₇, SO₃, H₂S etc.
Carbon compounds include oxides of carbon (CO + CO₂) and hydrocarbons.
Nitrogen compounds are NO₂ and NH₃
Halogen compounds are hydrogen fluoride (HF) and HC₁.

(ii) Secondary pollutants: The secondary pollutants are produced by the combination of primary emitted pollutants in the atmosphere.

Effects of Pollutants on Animals and Man: Only some of the direct or indirect effects of airborne pollutants on animal life have been studied so far. The general effect of air pollutants is on the respiratory tract and lung causing pulmonary Oedema and lung cancer. In addition to irritation in eyes, mucous membrane and pulmonary congestion, chronic bronchitis, lung carcinoma and other effects.

Flourosis in cattle is caused if exposed to fluoride-containing dusts. More subtle physiological effects of ciliary action, alternation in pulmonary physiology, specific enzyme inhibition and changes in blood chemistry. Inhaling of ozone causes dryness of membrane of mouth, nose and throat changes, visual activity causes headache, pulmonary congestion and oedema. Radio-active elements which enter the air through nuclear explosions come by earth as nuclear follents. These enter the biological system the absorption through the leaves or roots of plants and often result in the formation of cancer.

Control of Air pollution: Air pollution is caused mostly by human agencies. The use of cheap fuels with higher sulphur contents should be avoided. Use of expensive fuels of high quality should be recommended. Strict check on car exhaust should be maintained for contents. The poisonous gases going out in the atmosphere should be treated chemically. The persons working in chemical factories, polishing and spray industries should be provided with suitable gas dust masks.

Question 24.
What is radiation pollution? What are the effects of it?
Answer:
When in atmosphere harmful changes happen due to different types of radiations and radio-active materials then it is called radiation pollution. It is the physical pollution of air, water and soil with radioactive materials. It is natural as well as man-made. The effect of radioactive pollutants depends on (i) strength of radiation, (ii) rate of diffusion and deposition of the pollutants, (iii) the length of time for which the tissue is exposed to radiation, and (iv) half-life of pollutants. Environmental factors also influence their effects.

Effects of radiation pollution :

1. Due to radiation pollution, body becomes weak and life becomes short.
2. Radiation pollution is harmful for DNA, RNA, Protein, Spleen, etc.
3. Radio-active radiations cause sterility, defect vision, tumour of lungs, loss of tissues, etc.
4. Long time exposure in ultraviolet radiations causes skin related diseases.
5. For long time or time-to-time radiation of radio active materials may cause blood cancer or Leuckaemia.
6. Cells vary in their sensitivity to injury by radiation.
7. Chances of depletion of ozone layer in stratosphere by nuclear explosions.

Bihar Board 12th Accountancy Model Papers

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

Time : 3 Hours 15 Min
Full Marks: 100

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. While answering the questions, the candidate should adhere to the word limit as for as practicable.
4. 15 minutes of extra time has been allotted for the candidate to read the questions carefully.
5. This question paper has two sections: Section – A and Section – B.
6. In Section – A, there are 50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with black/blue ball pen against the correct option on OMR Sheet provided to you. Do not use Whitener/Liquid/Blade/Nail on OMR Sheet, otherwise, the result will be treated as invalid.
7. In Section – B there are Non-objective type questions. There are 25 Short answer type questions, out of which any 15 questions are to be answered. Each question carries 2 marks. Apart from this, there are 8 Long answer type questions, out of which any 4 of them are to answer. Each question carries 5 marks.
8. Use of any electronic device is prohibited.

Objective Type Questions

Question No. 1 to 50 have four options, out of which only one is correct, you have to mark the correct option on the OMR Sheet. (50 × 1 = 50)

Question 1.
Income & Expenditure Account is
(a) Personal A/c
(b) Real A/c
(c) Nominal A/c
(d) None of these
Answer:
(c) Nominal A/c

Question 2.
Legacy should be treated as
(a) liability
(b) capital receipt
(c) revenue receipt
(d) None of these
Answer:
(a) liability

Question 3.
Specific donation is
(a) Capital Receipt
(b) Revenue Receipt
(c) Assets
(d) None of these
Answer:
(a) Capital Receipt

Question 4.
Subscriptions received by an organisation is
(a) Capital Receipt
(b) Revenue Receipt
(c) Both
(d) None of these
Answer:
(b) Revenue Receipt

Question 5.
Current Account is
(a) Personal A/c
(b) Real A/c
(c) Nominal A/c
(d) None of these
Answer:
(a) Personal A/c

Question 6.
Making partnership agreement is
(a) compulsory
(b) voluntary
(c) partly compulsory
(d) None of these
Answer:
(a) compulsory

Question 7.
For the firm interest on partner’s drawing is a/an
(a) expense
(b) income
(c) loss
(d) receipt
Answer:
(b) income

Question 8.
In the partnership firm, profit and loss are shared
(a) equally
(b) ratio of capital
(c) according to agreement
(d) none of these
Answer:
(c) according to agreement

Question 9.
P/L Appropriation A/c is prepared
(a) for reserve fund
(b) for net profit
(c) for divisible profit
(d) none of these
Answer:
(c) for divisible profit

Question 10.
Interest on advance given to the firm is
(a) an appropriation
(b) profit
(c) charge
(d) none of these
Answer:
(c) charge

Question 11.
The excess of average profit over the normal profit is called
(a) super profit
(b) Fixed profit
(c) Abnormal profit
(d) normal profit
Answer:
(a) super profit

Question 12.
The monetary value of the reputation of the business is called
(a) goodwill
(b) surplus
(c) abnormal profit
(d) none of these
Answer:
(a) goodwill

Question 13.
Profit or loss on revaluation is borne by
(a) old partners
(b) new partners
(c) all partners
(d) only two
Answer:
(a) old partners

Question 14.
Excess of the credit side over the debit side of Revaluation Account is
(a) profit
(b) loss
(c) receipt
(d) expense
Answer:
(a) profit

Question 15.
The opening balance of Partner’s Capital A/c is credited with
(a) interest on capital
(b) interest in drawing
(c) drawing
(d) share in loss
Answer:
(a) interest on capital

Question 16.
Share of goodwill brought in cash by the new partner is called
(a) Assets
(b) Profit
(c) Premium
(d) none of these
Answer:
(c) Premium

Question 17.
On the retirement of a partner, the full amount of goodwill is credited to the capital accounts of
(a) retiring partner
(b) remaining partners
(c) all partners
(d) none of these
Answer:
(d) none of these

Question 18.
Gaining Ratio is calculated
(a) at the time of admission
(b) at the time of retirement
(c) on the dissolution
(d) none of these
Answer:
(b) at the time of retirement

Question 19.
Profit & Loss on Revaluation at the time of retirement is shared by
(a) remaining partners
(b) all partners
(c) new partners
(d) none of these
Answer:
(a) remaining partners

Question 20.
A, B and C are partners sharing profit & loss in the ratio of 5 : 3 : 2. A retires. The gaining ratio is
(a) 3 : 2
(b) 5 : 3
(c) 5 : 2
(d) None of these
Answer:
(c) 5 : 2

Question 21.
The amount due to the deceased partner is paid to his
(a) Father
(b) Friend
(c) Wife
(d) Executors
Answer:
(d) Executors

Question 22.
On the death of a partner in a firm final payment are made to
(a) Capital A/c
(b) Executor A/c
(c) Current A/c
(d) Loan A/c
Answer:
(b) Executor A/c

Question 23.
The executors of a deceased partner will be paid interest on the amount from the date of death of the partner at
(a) 5% p.a.
(b) 6% p.a.
(c) 7% p.a.
(d) 8% p.a.
Answer:
(b) 6% p.a.

Question 24.
Joint life policy of the partners is an _______ account.
(a) nominal A/c
(b) personal A/c
(c) liability
(d) goodwill.
Answer:
(b) personal A/c

Question 25.
Revaluation A/c is prepared at the time of
(a) Admission
(b) Retirement
(c) Death
(d) All of these
Answer:
(d) All of these

Question 26.
Payment of credit balance of partners Capital Account at the time dissolution of a firm is made to
(a) partners
(b) firm
(c) wife
(d) none of these
Answer:
(a) partners

Question 27.
Realisation expenses are recorded in which side of Realisation Account?
(a) Liabilities
(b) Assets
(c) Debit
(d) Credit
Answer:
(b) Assets

Question 28.
At the time of dissolution of the firm book value of assets is recorded in which side of the Realisation A/c?
(a) Debit side
(b) Credit side
(c) Liabilities side
(d) Assets side
Answer:
(a) Debit side

Question 29.
Realisation Account is a
(a) Personal A/c
(b) Nominal A/c
(c) Real A/c
(d) None of these
Answer:
(b) Nominal A/c

Question 30.
On the dissolution of a firm, Partners Capital A/c is closed through
(a) Realisation A/c
(b) Drawing A/c
(c) Bank A/c
(d) None of these
Answer:
(c) Bank A/c

Question 31.
Expenses on the dissolution of a firm is called
(a) Realisation expense
(b) Legal expense
(c) Loss expenses
(d) None of these
Answer:
(a) Realisation expense

Question 32.
A firm can be voluntarily dissolved by the partners
(a) on majority’s decision
(b) on \(\frac{3}{4}\) of the member’s decision
(c) on \(\frac{1}{2}\) of the member’s decision
(d) none of these
Answer:
(b) on \(\frac{3}{4}\) of the member’s decision

Question 33.
On the firm’s dissolution which one of the following A/c should be prepared at the last?
(a) Realisation A/c
(b) Cash A/c
(c) Capital A/c
(d) Loan A/c
Answer:
(a) Realisation A/c

Question 34.
On dissolution, Goodwill A/c is transferred to
(a) Realisation A/c
(b) Capital A/c
(c) Drawing A/c
(d) Loan A/c
Answer:
(a) Realisation A/c

Question 35.
At the time of dissolution of a firm. Balance of general reserve shown in the Balance sheet is credited to
(a) Realisation A/c
(b) Creditors A/c
(c) Capital A/c
(d) Profit & Loan A/c
Answer:
(c) Capital A/c

Question 36.
Cash balance shown in the Balance Sheet is shown on the dissolution of the firm in
(a) Realisation A/c
(b) Cash A/c
(c) Capital A/c
(d) None of these
Answer:
(b) Cash A/c

Question 37.
On dissolution of a firm. Bank overdraft is transferred to
(a) Cash A/c
(b) Bank A/c
(c) Realisation A/c
(d) Capital A/c
Answer:
(c) Realisation A/c

Question 38.
On dissolution of a firm, Partners Loan A/c is transferred to
(a) Realisation A/c
(b) Capital A/c
(c) Current A/c
(d) None of these
Answer:
(c) Current A/c

Question 39.
Shares may be issued
(a) at par
(b) at premium
(c) at discount
(d) all of these
Answer:
(d) all of these

Question 40.
Equity shareholders are _______ of the company.
(a) Bankers
(b) Creditors
(c) Debtors
(d) Owners
Answer:
(d) Owners

Question 41.
Money received from a dead man’s legacy is called
(a) Legacy
(b) Honorarium
(c) Donation
(d) Subscription
Answer:
(a) Legacy

Question 42.
Payment of honorarium to the secretary is:
(a) Capital expenditure
(b) Revenue expenditure
(c) Cash expenditure
(d) Deferred Revenue Expenditure
Answer:
(b) Revenue expenditure

Question 43.
Interest is to be given a partner to the firm in the absence of partnership deed.
(a) 5%
(b) 6%
(c) 8%
(d) 9%
Answer:
(b) 6%

Question 44.
Interest on capital will be given to the partners in the absence of a partnership agreement
(a) 5%
(b) 6%
(c) 8 %
(d) nome of these
Answer:
(d) nome of these

Question 45.
The current account is:
(a) Personal A/c
(b) Real A/c
(c) Nominal A/c
(d) None of these
Answer:
(a) Personal A/c

Question 46.
Drawings of the partners debited to:
(a) Partners capital A/c
(b) Profit & Loss A/c
(c) P & L appropriate A/c
(d) Revaluation A/c
Answer:
(a) Partners capital A/c

Question 47.
Interest on parter’s capital is to be credited
(a) Profit & Loss A/c
(b) Realisation A/c
(c) Partners Capital A/c
(d) Revaluation A/c
Answer:
(c) Partners Capital A/c

Question 48.
Excess of real profit on general profit is called
(a) Super profit
(b) Definite profit
(c) Abnormal profit
(d) General profit
Answer:
(a) Super profit

Question 49.
A and B are the partners of profit is divided in 3 : 1. They give a \(\frac{1}{4}\) part of profit in future and admitted in. New profit-distribution ratio is:
(a) Explanation/Working
(b) A \frac{81}{16}: B \frac{4}{16}: C \frac{4}{16}
(c) \(A \frac{10}{16}: B \frac{2}{16}: C \frac{4}{16}\)
(d) \(A \frac{8}{16}: B \frac{9}{16}: C \frac{10}{16}\)
Answer:
(a) Explanation/Working

Question 50.
X and Y are partners of profit into 3 : 2. Z become partner for \(\frac{1}{5}\) share Z takes from X \(\frac{3}{20}\) and from Y \(\frac{1}{20}\). Then new profit ratio is:
(a) 9 : 7 : 4
(b) 8 : 8 : 4
(c) 6 : 10 : 4
(d) 10 : 6 : 4
Answer:
(a) 9 : 7 : 4

Non-Objective Type Questions

Short Answer Type Questions

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

Question 1.
What Journal entry will be recorded for the amount payable to a deceased partner?
Answer:
Profit and Loss of Suspense A/c … Dr.
To deceased partner’s capital A/c
(Being deceased partner’s capital A/c credited with his share in profit)

Question 2.
On dissolution, what entry is passed if a partner takes over an asset of the firm?
Answer:
Partner’s capital A/c …Dr.
To Realisation A/c
(Being assets were taken over by partners.)

Question 3.
State four features of Receipts and Payments Account.
Answer:
Following are the four features of Receipt and Payment Account:

• It is a Real Account
• It records all receipts whether it Revenue or capital in nature in the debit side
• It records all Payments in credit side, whether it is revenue or capital in native
• It doesn’t record any non-cash item. i.e. Depreciation, outstanding etc.

Question 4.
State four features of a partnership.
Answer:
Following are the essential features of a partnership firm:

• Two or More Persons: There must be two or more competent Persons to form a Partnership firm.
• Agreement between the Partners: Partnership is created by an agreement which forms the basis of mutual rights and duties of Partners. This agreement may be either oral or in writing.
• Engagement in legal business: The Partnership should be for carrying on some legal business with the intention of earning profits.
• Sharing of Profit: Profit earned should be divided amongst Partners in the agreed Profit sharing ratio.

Question 5.
Explain three factors affecting goodwill.
Answer:
Some Following Factors affecting the value of goodwill.

• Location: A Favourable location of the business helps to a great extent in attracting customers.
• Nature of Business: The nature of the business also affects the value of goodwill.
• Time: An older business will have more goodwill since it is better known to the customers.
• Risk Involved: The more the risk involves in the business, less the nature of goodwill.

Question 6.
Distinguish between the Average Profit Method and Super Profit Method of calculating goodwill.
Answer:
Distinguishment between Super profit method and Average profit method of calculating goodwill. Super profit method Under this method, super profits constitute the basis of calculation of the value of goodwill. And hence, goodwill is calculated by multiplying the super-profits by a reasonable number of years.
Formula:
Goodwill = Super profit × Agreed on number of year’s purchase.
Where Super profit = Actual average profit – Normal profit.
Average profit method: Under average profit method, goodwill is valued on the basis of the agreed number of years’ because of the average profits of the last few years.
Formula:
Goodwill = Average profit × Number of years purchase.

Question 7.
How will you calculate the amount due to a deceased partner?
Answer:

Question 8.
A, B and C are partners sharing the profit in the ratio of 3 : 2 : 1. They admit D for 1/6 the share. It is agreed that C would retain his original share. Calculate New Ratio.
Answer:

Question 9.
P, Q and R are partners sharing profits in the ratio of 5 : 4 : 3. Q retires and his share was divided equally between P and R. Calculate new profit sharing ratio of P and R.
Answer:
Q’s Share will be divided between P and R equally:

Question 10.
Distinguish between the dissolution of partnership and dissolution of the firm.
Answer:
Difference between the dissolution of partnership and dissolution of firm are as fellow:

• Change in relation: The dissolution of the firm implies a complete break-down of the partnership relationship between all the partners whereas dissolution of the partnership merely involves a change in the relation of the partners.
• Continuance of business: In the case of dissolution of a firm the business comes to an end whereas in case of dissolution of partnership the business of the firm is continued.
• Effect: Dissolution of partnership does not necessarily mean the dissolution of the firm whereas dissolution of the firm necessarily implies the dissolution of a partnership.
• Closure of Books of Accounts: On dissolution of the firm all accounts books are closed whereas in case of dissolution of partnership closure of books is not required.
• Nature: Dissolution of the partner is voluntary whereas dissolution of the firm is voluntary and compulsory.
• Court order: The firm may be dissolved by the order of the court whereas dissolution of the partnership is a process of reconstitution.
• Disposal of Assets and Liabilities: In case of dissolution of partnership assets and liabilities are revalued and new Balance sheet is drawn. But in case of dissolution of a firm, assets are realised and liabilities are paid off.

Question 11.
In what circumstance can a firm be dissolved?
Answer:
Following are the circumstances under which a firm can be dissolved

• Retirement of any of the partner
• Death of any of the partner
• Any of the partners declared as insolvent
• The incapability of any partner
• Completion of the venture
• At the expiry of the term of the partnership.

Question 12.
State the ways of redemption of debentures.
Answer:

• Payment in annual Installment
• Purchase own debenture in the open market

Question 13.
State two objectives of Financial Statements.
Answer:
Two objectives of Financial statements

• Source of Financial Information
• Help in Financial Forecasting
• Information about Earning capacity.

Question 14.
State two limitations of analysis of Financial Statement.
Answer:
Two Limitation of Financial Analysis

• Lack of Preciseness
• The problem of Interpretation.

Question 15.
State two objectives of ratio analysis.
Answer:
Two objectives of ratio analysis

• To measure the profitability of the concern
• To assess the solvency of the business
• Facilitate comparative analysis.

Question 16.
Give two examples of cash flow from operating activity.
Answer:
Two examples

• Cash sale of goods
• Receipt from debtors.

Question 17.
What do you mean by Fixed Charges and Floating Charges?
Answer:
Fixed charges are made on specific assets of a company, on the other hand. Floating charges are made on
General assets of a company.

Question 18.
What is the difference between Reserve and Provision?
Answer:

Provision	Reserve
(i) Provision is made for a specific loss or liability.	(i) Reserve is made for uncertain liability.
(ii) Its object to meet the know loss or deprecitation.	(ii) Its object is to increase in working capital and meet to unknown loss.
(iii) It is Compulsory to make Provision.	(iii) It is made only when company earn Profit.

Question 19.
What is meant by Analysis of Financial Statement?
Answer:
The analysis is the process of critically examining the accounting information given in financial statements. For this purpose of analysis, individual items are studies, their inter-relationship with other related figures is established.
According to Finley and Miller,”Financial analysis consists in separating facts according to some definite plan, arranging them in groups according to certain circumstances and then presenting them in a convenient and easily readable and understandable form.”

Question 20.
What is meant by Comparative Financial Statement?
Answer:
Comparative Financial Statement: Statement showing financial data of Balance Sheet or profit & loss statement for two or more than two years, placed side by side to facilitates comparison is called comparative financial statements. This type of analysis is called horizontal analysis.

Question 21.
Distinguish between preference share and equity share.
Answer:

Basis	Preference Shares	Equity Shares
1. Rate of dividend	The rate of dividend on Preference shares is fixed.	The rate of dividend on equity shares is changed year to year.
2. Payment of dividend	Preference shares holder has the right to receive the dividend before making any Payment out of Profit.	Dividend on equity shareholders is paid only when a dividend is paid on Pref. shares.
3. Management.	Preference shareholders are not entitled to participate in management.	Equity Shareholders are entitled to participate in management.

Question 22.
State any three differences between shareholders and debenture holders.
Answer:

Shareholders	Debenture holders
(i) Shareholders are the owner of the company.	(i) Debenture holders are creditors of the company.
(ii) Shareholders is get paid dividend on their shares.	(ii) A debenture holder is get paid interest on their debenture at fixed-rate
(iii) Shareholders have the right to participate in management.	(iii) Debenture holder has no right to participate in management.

Question 23.
Why is Cash flow statement prepared?
Answer:
Cash Flow Statement is one of the important tools of cash management because it throws light on cash inflows of cash equivalents during a specific period. This statement exhibits the flow of incoming cash. This statement assesses the ability of the enterprise to generate cash and utilise the cash. And so cash flow statement is one of the tools for assessing the liquidity and solvency of the enterprises.

Question 24.
Current Ratio is 2 : 1. Working Capital is Rs. 1,50,000. Calculate the amounts of current assets and current liabilities.
Answer:

Question 25.
What do you mean by the company? State its essential features.
Answer:
A company means a company incorporated or registered under the Companies Act, 2013 or under any other earlier companies Act.

It a voluntary association of persons formed for some common purpose having a capital divided into transferrable shares. It is created by law and effected by law. A company may be defined as an artificial person created by law, having perpetual succession and a common seal.

According to L.H. Haney. “A company is an artificial person created by law having a separate entity with perpetual succession and a common seal. It is a voluntary association of individuals for-profits, having a capital divided into transferrable shares ownership of which is the condition of membership.”

Following are the essential features of the company:

• Association of persons: A company is an association of persons, usually for profit.
• Artificial person: It is an artificial person created by law.
• Separate legal entity: It has a separate legal entity from its members. So it can be sued in its own name. It can own or dispose of the property in its own name.
• Limited liability: It has limited liability. Liability of members is limited to the extent of the face value of shares need by them.
• Perpetual succession: A company being an artificial person never dies. It is a creation of law, so, its existing law. It is not affected by the death of shares held by them.
• Common seal: It has a common seal which acts as the official signature of the company. Any document without the common seal of the company is not binding on the company.
• Transferability of shares: The capital of a company is divided into shares. The shares of a company are transferable except in case of a private company.
• Separate ownership and management: In companies, there is a divorce between ownership and management. It is owned by members (shareholders) but it is managed by the Board of Directors who are elected by shareholders. Members of a company can not directly participate in the management of the business of the company.

Long Answer Type Questions

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

Question 26.
Form the following statement of profit and loss of the year ended 31st March 2014, prepare a comparative statement of profit and loss of X Ltd:

Answer:

Question 27.
Receipts and Payments A/c of Maitree Club for the year ended March 31, 2013, shows that the subscriptions received were Rs. 25,000. Additional information is as follows:

Ascertain the amount of income from a subscription for the year 2012-13 and show how relevant items of subscriptions appear in Opening and Closing Balance Sheet.
Answer:
Statement showing Income from a subscription for the year ended 2012-13

Question 28.
A, B and C are equal partners. Their fixed capitals as on 1st April. 2012 were A Rs. 10,000, B Rs. 20,000 and C Rs. 30,000. Profits for the year 2012-13 amounted to Rs. 12,000 which were distributed. Give the necessary Journal entries if the interest on capital was credited @ 10% p.a. instead of 12% p.a.
Answer:

Question 29.
X, Y and Z are partners in a firm in the ratio of 3 : 2 : 1. On 1st April 2013 they decided to share profits in future in the ratio of 7 : 5 : 4. On that date general reserve is Rs. 76,000 and profit on revaluation of assets and liabilities being Rs. 68,000. It was decided that adjustment should be made without altering the figures in the Balance Sheet. Make adjustment by one Single Journal entry.
Answer:

Question 30.
A, B and C are partners sharing profits and losses equally. They dissolved the firm on 30th December 2013 on which date their positions were as under:

All the assets realise less than 10% book value. Creditors were paid in full. Expenses of realisation amounted to Rs. 500. Prepare Realisation account. Partners Capital account and cash or bank account.
Answer:

Question 31.
Rudra Company Ltd. issued 35,000 equity shares of Rs. 10 each at a premium of Rs. 2 payable as follows:
On Application – Rs. 3
On Allotment – Rs. 5
The balance on the first call
Record Journal entreis.
Answer:

Question 32.
Urvashi Ltd. purchased one established business for Rs. 50,000 payable Rs. 15,000 in cash and the balance by Issue of 9% debentures of Rs. 100 at a discount of 10%. Give journal entries in the books of Urvashi Ltd.
Answer:

Question 33.
From the following data, prepare a statement of profits in the comparative form:

Answer:

Bihar Board 12th Accountancy Model Papers

Bihar Board 12th Accountancy Model Question Paper 2 in English Medium

Time : 3 Hours 15 Min
Full Marks: 100

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. While answering the questions, the candidate should adhere to the word limit as for as practicable.
4. 15 minutes of extra time has been allotted for the candidate to read the questions carefully.
5. This question paper has two sections: Section – A and Section – B.
6. In Section – A, there are 50 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with black/blue ball pen against the correct option on OMR Sheet provided to you. Do not use Whitener/Liquid/Blade/Nail on OMR Sheet, otherwise, the result will be treated as invalid.
7. In Section – B there are Non-objective type questions. There are 25 Short answer type questions, out of which any 15 questions are to be answered. Each question carries 2 marks. Apart from this, there are 8 Long answer type questions, out of which any 4 of them are to answer. Each question carries 5 marks.
8. Use of any electronic device is prohibited.

Objective Type Questions

Question No. 1 to 50 have four options, out of which only one is correct, you have to mark correct option on the OMR Sheet. (50 × 1 = 50)

Question 1.
Receipts and Payments Account usually indicates:
(a) Surplus
(b) Capital fund
(c) Debit Balance
(d) Credit Balance
Answer:
(c) Debit Balance

Question 2.
Receipts and Payments Account is a:
(a) Personal Account
(b) Real Account
(c) Nominal Account
(d) None of these
Answer:
(b) Real Account

Question 3.
Outstanding subscription is a:
(a) Income
(b) Asset
(c) Both ‘A’ and ‘B’
(d) None of these
Answer:
(b) Asset

Question 4.
Income and Expenses related to the prize fund is shown in:
(a) Income and Expenditure Account
(b) The asset side of the Balance sheet
(c) Liabilities side of the Balance sheet
(d) Cash Account
Answer:
(a) Income and Expenditure Account

Question 5.
Income and Expenditure Account records:
(a) All cash receipts and payments
(b) All credit receipts and payments
(c) All cash and credit receipts and payments
(d) None of these
Answer:
(a) All cash receipts and payments

Question 6.
Which sequence is correct and appropriate?
(a) Cashbook, Receipts & Payment Account, Income & Expenditure Account and Balance sheet.
(b) Receipts and Payments Account, Cash Book, Income and Expenditure Account and Balance sheet
(c) Income and Expenditure Account, Receipts and Payments account, cash book and Balance sheet.
(d) None of these
Answer:
(c) Income and Expenditure Account, Receipts and Payments account, cash book and Balance sheet.

Question 7.
The main aim of the Not-for-Profit organisation is:
(a) To earn profit
(b) To serve society
(c) To earn profit and serve society
(d) All the above
Answer:
(b) To serve society

Question 8.
Payment of Honorarium to Secretary is a:
(a) Revenue Expenditure
(b) Capital Expenditure
(c) Both
(d) None of these
Answer:
(a) Revenue Expenditure

Question 9.
Which of the following statements is correct?
(a) There is no difference between Cash Book and Receipts and Payments Account
(b) Receipts and Payments Account is prepared after Cash Book
(c) Receipts and Payments Account is maintained by Non-trading concern whereas Cash Book is maintained by the Trading concern
(d) Receipts and Payment Account is prepared before Cash Book
Answer:
(c) Receipts and Payments Account is maintained by Non-trading concern whereas Cash Book is maintained by the Trading concern

Question 10.
When the time of withdrawals is not mentioned, interest on drawings is charged:
(a) For 6 1/2 months
(b) For 6 months
(c) For 5 1/2 months
(d) For 12 months
Answer:
(b) For 6 months

Question 11.
Recording of the unrecorded asset on the reconstitution of a partnership firm will be.
(a) Again to the existing partner
(b) A loss to the existing partner
(c) Neither a gain nor a loss to the existing partner
(d) None of these
Answer:
(b) A loss to the existing partner

Question 12.
Current Account is:
(a) Personal Account
(b) Real Account
(c) Nominal Account
(d) None of these
Answer:
(a) Personal Account

Question 13.
In which ratio, the cash brought in for goodwill by the new partner is shard by the existing partners.
(a) Profit-Sharing Ratio
(b) Capital Ratio
(c) Sacrificing Ratio
(d) None of these
Answer:
(c) Sacrificing Ratio

Question 14.
A, B and C are three partners sharing profits and losses in the ratio of 4 : 3 : 2. D is admitted for 1/10th share, the new ratio will be:
(a) 10 : 7 : 7 : 4
(b) 5 : 3 : 2 : 1
(c) 4 : 3 : 2 : 1
(d) None of these
Answer:
(c) 4 : 3 : 2 : 1

Question 15.
The executors will be paid interest on the amount due from the date of death of the partner @
(a) 4%
(b) 5%
(c) 6%
(d) 7%
Answer:
(c) 6%

Question 16.
Realisation Account is a:
(a) Personal Account
(b) Nominal Account
(c) Real Account
(d) None of these
Answer:
(b) Nominal Account

Question 17.
A firm can be voluntarily dissolved by the partners:
(a) On Majority basis
(b) On 3/4 Member’s decision
(c) On 1/2 Member’s decision
(d) None of these
Answer:
(a) On Majority basis

Question 18.
Unrecorded liabilities when paid will be shown in:
(a) The debit side of Realisation Account
(b) Debit side of Bank Account
(c) Credit side of Realisation Account
(d) Credit side of Bank Account
Answer:
(a) The debit side of Realisation Account

Question 19.
Who are the owners of the company?
(a) Equity shareholders
(b) Preference shareholders
(c) Debenture holders
(d) Both A & B
Answer:
(a) Equity shareholders

Question 20.
Forfeiture of shares results in the reduction of:
(a) Paid-up capital
(b) Authorised capital
(c) Fixed Assets
(d) Reserve capital
Answer:
(a) Paid-up capital

Question 21.
Profit on cancellation of own debentures is transferred to:
(a) Profit and Loss Account
(b) Profit and Loss Appropriation Account
(c) General Reserve Account
(d) Capital Reserve Account
Answer:
(d) Capital Reserve Account

Question 22.
Interest on Sinking fund Investment is credited to:
(a) Profit and Loss Account
(b) Sinking fund Account
(c) General Reserve Account
(d) Sinking fund Investment Account
Answer:
(b) Sinking fund Account

Question 23.
Discount on issue of debentures is:
(a) Fixed Asset
(b) Current Asset
(c) Real Asset
(d) Factitious Asset
Answer:
(d) Factitious Asset

Question 24.
In case of issue of debentures as collateral security for a loan from the bank which account will be debited:
(a) Bank Account
(b) Bank Loan Account
(c) Debenture Account
(d) Debentures Suspense Account
Answer:
(c) Debenture Account

Question 25.
According to SEBI guidelines, a company will have to create debenture redemption reserve equivalent to the amount of the following percentage of debenture issued:
(a) 40%
(b) 50%
(c) 70%
(d) 100%
Answer:
(b) 50%

Question 26.
As per the provisions of Companies Act, 2013 under which section, the final Accounts of a company is prepared:
(a) 128
(b) 210
(c) 129
(d) 212
Answer:
(b) 210

Question 27.
Out of the following which parties are interested in financial statement?
(a) Managers
(b) Financial Institutions
(c) Creditors
(d) All of these
Answer:
(d) All of these

Question 28.
Debt-Equity Ratio is:
(a) Liquidity ratio
(b) Activity Ratio
(c) Solvency Ratio
(d) Operating ratio
Answer:
(c) Solvency Ratio

Question 29.
When the opening stock is 50,000 Rs closing stock 60,000 Rs and cost of goods sold is 2,20,000 Rs then stock Turnover Ratio is:
(a) 2 times
(b) 3 times
(c) 4 times
(d) 5 times
Answer:
(c) 4 times

Question 30.
Cash flow statement is related to:
(a) AS – 3
(b) AS – 6
(c) AS – 09
(d) AS – 12
Answer:
(a) AS – 3

Question 31.
Which of the following activity comes under Financial Activities?
(a) Receipts from the issuance of Equity shares
(b) Cash sales
(c) Bank overdraft
(d) Purchase of Debentures
Answer:
(a) Receipts from the issuance of Equity shares

Question 32.
Which of the following item is not considered as cash equivalents?
(a) Bank overdraft
(b) Commercial paper
(c) Treasury Bills
(d) Investment
Answer:
(d) Investment

Question 33.
Cash from operating activities will decrease due to:
(a) Increase in current Assets
(b) The decrease in current liabilities
(c) Neither of the two
(c) Both (a) and (b)
Answer:
(b) The decrease in current liabilities

Question 34.
The term Quick assets do not include:
(a) Stock
(b) Debtors
(c) B/R
(d) Cash and Bank Balance
Answer:
(a) Stock

Question 35.
Dividends are usually paid on:
(a) Authorised capital
(b) Issued capital
(c) Called up capital
(d) Paid-up capital
Answer:
(d) Paid-up capital

Question 36.
The nominal capital is known as:
(a) Authorised Capital
(b) Registered Capital
(c) Both (a) and (b)
(d) None of these
Answer:
(c) Both (a) and (b)

Question 37.
When a partner takes responsibility to make the payment of any outside liability of a firm, the account credited will be:
(a) Realisation account
(b) Cash Account
(c) partner’s capital Account
(d) None of these
Answer:
(c) partner’s capital Account

Question 38.
Cash balance shown in the Balance sheet is shown on the dissolution of the firm in:
(a) Realisation Account
(b) Cash Account
(c) Capital Account
(d) Profit and Loss Account
Answer:
(b) Cash Account

Question 39.
‘x’ and ‘y’ share profit in the ratio of 3 : 2. ‘z’ was admitted as a partner who gets 1/5 share, z acquires 3/20 share from ‘x’ and 1/20 from y. The new profit sharing ratio will be:
(a) 9 : 7 : 4
(b) 8 : 8 : 4
(c) 6 : 10 : 4
(d) 10 : 6 : 4
Answer:
(a) 9 : 7 : 4

Question 40.
partner’s current Account is prepared when the capital of partners is maintained under:
(a) Fluctuating basis
(b) Fixed basis
(c) In both of the situations
(d) None of these
Answer:
(a) Fluctuating basis

Question 41.
The amount received from the issue of debentures is:
(a) Capital receipts
(b) Revenue Receipts
(c) Capital and Revenue Receipt
(d) Neither capital nor revenue
Answer:
(a) Capital receipts

Question 42.
The Ideal Quick Ratio is:
(a) 2 : 1
(b) 1 : 1
(c) 0.5 : 1
(d) None of these
Answer:
(b) 1 : 1

Question 43.
Goodwill is:
(a) Fixed Assets
(b) Intangible Assets
(c) Fictitious Asset
(d) Both (a) & (b)
Answer:
(b) Intangible Assets

Question 44.
Provision for Taxation is:
(a) Current liability
(b) Interval Reserve
(c) Both (a) & (b)
(d) None of these
Answer:
(a) Current liability

Question 45.
Interest payable on debentures is:
(a) A charge against profit
(b) Appropriation of profit
(c) Both (a) & (b)
(d) None of these
Answer:
(a) A charge against profit

Question 46.
The formula of sacrificing ratio is:
(a) New Ratio-old Ratio
(b) Old Ratio-New Ratio
(c) Old Ratio-gaining Ratio
(d) None of these
Answer:
(b) Old Ratio-New Ratio

Question 47.
Subscription received in Advance is:
(a) Asset
(b) Liability
(c) Income
(d) None of these
Answer:
(b) Liability

Question 48.
Right shares are the shares which:
(a) Are issued to directors of the company
(b) Are issued to existing shareholders of the company
(c) Are issued to promoters in consideration of their services
(d) Are issued to vendors for purchasing assets
Answer:
(c) Are issued to promoters in consideration of their services

Question 49.
When the current ratio is 2 : 5 and the amount of current liabilities is 25000 Rs, what is the amount of current assets?
(a) ₹ 62,500
(b) ₹ 12,500
(c) ₹ 10,000
(d) None of these
Answer:
(b) ₹ 12,500

Question 50.
Which one of the following is a non-cash item?
(a) Depreciation
(b) Goodwill wrote off
(c) Both (a) & (b)
(d) None of these
Answer:
(a) Depreciation

Non-Objective Type Questions

Short Answer Type Questions

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

Question 1.
What is Income and Expenditure Account?
Answer:
Income and expenditure Account is a Nominal Account. It is a summary of incomes and expenses for a
particular accounting period.lt is like a profit and loss account of a business concern. Thus, an income and expenditure Account is a revenue account of a non-profit organisation. It serves the same purpose as the profit and loss Account in trading concerns.

Question 2.
What are the Current Assets?
Answer:
Current assets is a balance sheet account that represents the value of all assets that can reasonably expect to be converted into cash within one year. Current assets include cash and cash equivalents, accounts receivable, inventory, prepaid, marketable securities etc.

Question 3.
Define the Sinking fund.
Answer:
A sinking fund is a means of repaying funds borrowed through a bond issue through periodic payments to a trustee who retires part of the issue by purchasing the bonds in the open market. Rather than the issuer repaying the entire principal of a bond issue on the maturity date, another company buy back a portion of the issue annually and usually at fixed par value or at the current market value of the bonds whichever is less.

Question 4.
Distinguish between the Current Ratio and Quick Ratio.
Answer:
The main difference between the current ratio and the quick ratio is that the letter offers a more conservative view of the company’s ability to meets its short-term liabilities with its short-term assets because it does not include inventory and other current assets that are more difficult to liquidate. By excluding inventory the quick ratio focuses on the company’s more liquid assets.

Question 5.
Explain four characteristics of a Partnership firm.
Answer:
Following are the feature of a partnership firm:

• Two or more persons
• Agreement
• Profit-sharing
• Mutual agency.

Question 6.
What is Super Profit?
Answer:
Super profit is the excess of average profits over normal profits. Under this method, goodwill is calculated on the basis of super-profits.

Question 7.
What is a Financial Statement?
Answer:
The end product of financial accounting is financial statements. Financial statements are organised summaries of detailed information about the financial position and performance of enterprises for a particular period. Financial statements are also called financial report. The term ‘Financial statement’ normally refers to two basic statements, namely.

• Balance sheet
• Statement of profit loss.

Question 8.
What is Cash Flow Statement?
Answer:
Meaning of Cash Flow Statement: A statement of changes in financial position on a cash basis is commonly known as the cash flow statement. It shows the changes in cash position from one accounting period to another. In other words, the cash flow statement summarises the causes of changes in cash and cash equivalents position between dates of two Balance Sheets. It indicates the sources and uses of cash. This statement attempts to analyse the transactions of the firm in terms of cash. Thus, a Cash Flow Statement can be defined as a statement which summarises sources of cash inflows and uses of cash outflows of the firm during a particular period of time, says, a month or a year.

Question 9.
Distinguish between Realisation Account and Revaluation Account.
Answer:
Revaluation Account is prepared only when there is any change in the value of asset and liabilities of the partnership firm at the time of admission, retirement, and death of a partner. On the other hand, Realisation Account is opened when the firm goes into liquidation, so as to close the books of account and also to compute the effect (profit or loss) arising due to the realisation of assets and settlement of liabilities.

Question 10.
What is over-subscription of shares?
Answer:
When the number of shares applied for is more than the number of shares offered to the public the issue as said to be over-subscribed. However, a company cannot allot shares more than those offered for subscription.

Question 11.
Distinguish between Gaining Ratio and Sacrificing Ratio.
Answer:
Difference between sacrificing Ratio and Gaining ratio
Sacrificing Ratio:

• It is the ratio in which the old partners surrender their share of profit in favour of the new partner.
• It is calculated at the time of admission of a new partner.
• The purpose of calculating sacrificing ratio is to calculate the share of goodwill payable to old partners at the time of admission of a partner.
• Old Partner’s Capita! Account increase with the amount received as goodwill. New partner losses.
• It is calculated by deducting the new ratio from the old ratio.
• New Partner’s Capital A/c Dr. To Old Partner’s Capital A/c (In sacrificing ratio)

Gaining Ratio:

• It is the ratio in which the remaining partners share the retiring partner’s share of profit.
• It is calculated at the time of retirement or death of a partner.
• The purpose of calculating gaining ratio is to calculate the share of goodwill payable to the retiring partner by each of the remaining partners.
• Retiring partner gains and the remaining partners capital reduces, so they lose.
• It is calculated by deducting the old ratio from the new ratio.
• Remaining Partner’s Capital A/cs Dr. To Retiring Partner’s Capital A/c.

Question 12.
What is the forfeiture of shares?
Answer:
The term ‘forfeit’ means taking away of a thing or property on breach of a condition or default. A shareholder is liable to pay all the calls made by the company within the stipulated time. If a shareholder fails to pay allotment money and/or call money due on the shares held by him the company has right to forfeit such shares. But the company will have to follow the procedures specified in its Articles of Association. To forfeit a share means to cancel the allotment of defaulting shareholders.

Question 13.
Define Prospectus.
Answer:
The prospectus is the basis of the agreement between the company and the shareholders who take the shares on the strength of the prospectus. If they have been misleading by any statement in or omission of a material fact from the prospectus, they may

• hold the directors responsible for the loss that he may have suffered and.
• rescind the contract for taking the shares.

Question 14.
Distinguish between Revenue profit and Capital profit.
Answer:
Following are the main difference between capital profit and revenue profit.
Mode of Earning: Capital profit is earned by selling of assets, shares and debentures at a price more than their book value and face value. Revenue profit is earned in the ordinary course of business.

Distribution: Capital profit is not available for the distribution to shareholders as a dividend. Revenue profit is available for the distribution to shareholders a dividend.

Use: Capital profit is transferred to capital reserve and used for meeting capital losses. Revenue profit is used to distribute dividend and create reserve and fund for various purpose.

Treatment: Capital profit is shown on the liabilities side of the balance sheet. Revenue profit is shown as a debit balance on the debit side of the trading and profit & loss accounts and asset side of the balance sheet as an accumulated loss.

Question 15.
What is Financial Analysis?
Answer:
The financial analysis consists in separating facts according to some definite plan arranging them in groups according to certain circumstances and then presenting them in a convenient and easily readable and understandable form.

Question 16.
Distinguish between Cash Book and Receipts and Payments Account.
Answer:
Difference between Receipts and Payment Account and Cash Book.

Basis	Receipts and payment A/c	Cash Book
1. Date	Entries are not made datewise.	All entries are made datewise.
2. Entries	Entries are made classified form.	Entries are made chronological form.
3. Period	This account is prepared at the end of the accounting year.	Cashbook is prepared on a daily basis.
4. Institue	This is prepared by the non-for-profit organisations.	This is prepared by all the organisations trading and non-trading.
5. Ledger folio	There is no column of ledger folio.	This has a separate column for ledger folio.
6. Side	The left side is receipts and right sides are payment side.	the left side is the debit side and the right side is the credit side.

Question 17.
What is an unlimited liability?
Answer:
The indefinite extent of liability to pay a firms debts or obligations, extending beyond the investments of the firm’s owner partners of shareholders to their personal assets. This extent of liability is assumed in an unlimited liability.

Question 18.
Distinguish between charge against profit and Appropriation of profit.
Answer:
Difference between Appropriation of profit and charge against profit.

Appropriation of profit	Charge against profit.
It is the distribution of net profit to various needs.	It is the deduction from revenue to ascertain net profit or a net loss.
It is made only if there is a profit.	It is made even if there is a loss.
It is done after the creation of all the charges.	It is done before the appropriation of profit.

Question 19.
Distinguish between Fixed capital and Fluctuating capital.
Answer:
Distinguish between Fixed Capital and Fluctuating Capital.

Basis	Fixed Capital	Fluctuating Capital
1. Number of a/c	There are two a/c for each partner: current a/c and capital a/c	There is only one a/c for each partner namely capital a/c
2. Balance in a/c	The balance in capital a/c in capital a/c remains the same year after year except for special circumstance.	The balance in capital a/c keeps on changing very frequently from year to year.
3. Adjustments	Adjustment relating to drawing interest on drawing, interest on capital etc. are made in current a/c	Adjustments relating to drawing intt. on drawing intt. on capital etc. are made in capital a/c
4. Nature of balance in a/c	Capital A/c always shows a credit balance. Balance of current A/c may be either debit or credit.	Capital A/c may have a debit balance or credit balance. Balance of current A/c does not arise in this case.

Question 20.
Write four items relating to Not-for-Proft organisation.
Answer:
Following are four items relating to Non-for-Profit organisations.

• Not-for-profit organisations are established for the welfare and service of society and their members.
• They promote art, culture, religion, education sports etc.
• They do not operate with the objective of earning profit.
• These organisations are set-up as charitable societies, trust or club etc.

Question 21.
Distinguish between ‘Charge against profit’ & ‘Appropriation out of profit.’
Answer:
Distinguish between “charge against profit” and Appropriation out of profit as discussed below.

Charge against Profit	Appropriation out of Profit
(i) It is the deduction from revenue to ascertain net profit or a net loss.	(i) It is a distribution of net profit to various heads.
(ii) It is made even if there is a loss.	(ii) It is made only if there is profit.
(iii) It is done before the appropriation of profit.	(iii) It is done after the creation of all charges.
(iv) This will be debited to P/L Appropriation A/c.	(iv) It will be debited to P/L A/c or debited to the respective provision A/c.

Question 22.
Why the valuation of goodwill is required? Give a minimum of three reasons.
Answer:
The need for valuation of goodwill as discussed below:

• If any partner is admitted
• If any partner retires from the firm
• If any partner dies
• If any firm is sold
• If a firm is converted into a Company.

Question 23.
A, B and C are partners sharing profits in the ratio of \(\frac{1}{2}: \frac{1}{3}: \frac{1}{6}\). Find out new profit sharing ratio if B retires.
Answer:
Old ratio of A, B and C = \(\frac{1}{2}: \frac{1}{3}: \frac{1}{6}\) or, \(\frac{3}{6}: \frac{2}{6}: \frac{1}{6}\) = 3 : 2 : 1
B. Retires, New Radio = 3 : 1

Question 24.
Under which circumstances, a partnership firm is deemed to be dissolved?
Answer:
Under the following circumstances, a partnership firm is deemed to be dissolved

• Retirement of any of the partner
• Death of my partner
• Any of partner declared as insolvent
• In capability of any partner
• completion of the ventures
• At the expiry of the term of the partnership.

Question 25.
A, B and C were partners sharing profits in the ratio of \(\frac{2}{6}, \frac{1}{2}\) and \(\frac{1}{6}\). A retires and surrenders \(\frac{2}{3}\)rd of his share in favour of B and remaining in favour of C. Calculate new ratio and gaining ratio.
Answer:
A’s share (2/6) will be divided between B and C in the ratio of \(\frac{2}{3}: \frac{1}{3}\)
B’s gain = \(\frac{2}{3}\) of \(\frac{2}{6}: \frac{4}{18}\);
C’s gain = \(\frac{1}{3}\) of \(\frac{2}{6}=\frac{2}{18}\)
New share = old share + gaining share
B’s new share = \(\frac{1}{2}+\frac{4}{18}=\frac{9+4}{18}=\frac{13}{18}\)
C’s new share = \(\frac{1}{6}+\frac{2}{18}=\frac{3+2}{18}=\frac{5}{18}\)
New ratio of B and C = \(\frac{13}{18}: \frac{5}{18}\) or 13 : 5

Long Answer Type Questions

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

Question 26.
From the following information, calculate goodwill by (i) Capitalization method and (ii) at 3 years purchase of super-profits:
(i) Total Assets ₹ 10,00,000
(ii) External liabilities ₹ 1,80,000
(iii) Normal Rate of Return 10%
(iv) Average Net Profit of the last five years ₹ 1,00,000
Answer:
Calculation of Goodwill by using capitalization method.

10,00,000 – 820,000
Goodwill = 120,000
Net Assets = Total Assets – Liabilities = 10,00,000 – 180,000 = 820,000
Calculation of Goodwill by using super profit methods.

Super profit = 100,000 – 82,000 = 18,000
Goodwill = 180,000

Question 27.
An Ltd. company issued 5000 shares of ₹ 100 each at a premium of ₹ 5 per share payable as ₹ 20 on Application, ₹ 35 on the allotment (including premium), ₹ 30 on the first call and the balance on the second call. All the amounts were duly received except the first call money on 500 shares and the final call money on 700 shares. These shares have been forfeited and re-issued at ₹ 80 per share. Give Journal entries to record the above transactions.
Answer:

Question 28.
What is Cash Flow statement? How is it prepared?
Answer:
Meaning of cash flow statement: cash flow statement can be defined on a statement which summarises sources of cash inflows and outflows of cash and cash equivalent of the firm from various business activities during a given period. Thus, this statement exhibits the flow of incoming and outgoing cash.

Calculation of Cash Flows from Operating Activities: Almost all the companies prepare its Income Statement on the accrual basis of accounting under which revenues are recorded when earned and expenses are recorded when incurred. Because of this, net profit, as shown by Income Statement will not be equal to cash generated by operating activities. Hence, there is a need to calculate cash flows from operating activities. AS-3 (Revised) suggests two methods of reporting cash flows from operating activities:
(1) Direct Method, and (2) Indirect Method.

1. Direct Method: Under the direct method, major classes of gross cash receipts and gross cash payments are considered. Under this method, cash receipts from operating activities, i.e., cash received from the sale of goods and rendering services, cash collected from customers and cash received from trading commission and royalties and cash payments for operating activities such as payment to creditors for goods and services, employees for their services etc. are disclosed. The difference between cash receipts and cash payments is the net cash flow from operating activities. A cash flow statement based on the direct method is a Profit & Loss Account on a cash basis.

2. Indirect Method: Under this method, net profit or loss is adjusted for the effects of transactions of noncash nature and non-operating nature and changes in current assets and liabilities.

Question 29.
Calculate current Assets of a company from the following information:
Stock Turnover Ratio = 4 times
Stock at the end is ₹ 20,000 more than stock in the beginning.
Sales ₹ 300,000 and Gross Profit Ratio is 20% of sales.
Current liabilities = ₹ 40,000
Quick Ratio = 0.75
Answer:
Sales 300,000, G.P Ratio = 20%;
Cost of Goods sold = Sales – G.P.;
GP = \(=300,000 \frac{\times 20}{100}=60,000\)
300000 – 60000 = 240000
Stock Turnover Ratio = \($\frac{\text { cost of Goodwill }}{\text { Aug.Stock }}$\)
4 = 240000/Aug.stock
Aug. Stock = 240,000/4 = 60,000
Let op. stock = x
So, cl. stock = x + 20,000
Avg. Stock = \(=\frac{x+x+20,000}{2}\) = 60,000
x + 10,000 = 60,000
x = 60,000 – 10,000 = 50,000
op. Stock = 50,000
Quick Ratio = Liquid Assets/CL. Liabilities
0. 75 = L. A/400,000
L. A. = 30,000
Current Assets = L.A + C.L. Stock = 30,000 + 70,000
C.A = 10,000

Question 30.
From the following particulars, Calculate Cash Flow from Investing Activities.
Investment at the beginning of the Period: 5,80,000
Investment at the end of the Period: 3,40,000
During the year the company had sold 50% of its investment held in the beginning of the period at a profit of ₹ 90,000
Answer:

Question 31.
Pass Journal entries when shares are issued at a premium.
Answer:
Journal entries where shares are issued at a premium.
I. When share premium is payable with application money.
(i) At the time of receipt of application money.
Bank A/c — Dr.
To share Application A/c
(ii) At the time of transfer of Application Money:
Share Application A/c
To share Capital A/c
To securities premium A/c

II. When the premium is payable on Allotment.
(i) Share Allotment A/c — Dr.
To share Capital A/c
To securities Premium A/c
(ii) On receipt of Allotment Money.
Bank A/c — Dr.
To share Allotment A/c

III. When the premium is payable with share call money.
(i) Share Call A/c — Dr.
To share Capital A/c
To securities Premium A/c
(ii) When call money is received.
Bank A/c — Dr.
To share call A/c

Question 32.
From the following comparative balance sheet prepare cash flow statement as on 31st December 2016.

Depreciation charged on machinery Rs. 5,000
Answer:
Calculation of cash flow statement from operating Activities.

Question 33.
Prepare an imaginary proforma of the cash flow statement.
Answer:
Imaginary proforma of cash flow statement

Bihar Board 12th Intermediate English Model Question Papers, Sample Papers 2019, 2020, 2021 with Answers Pdf free download.

Bihar Board 12th Intermediate English Model Question Papers 2020-2021 Pdf with Answers

Bihar Board 12th Model Papers

Bihar Board 12th English 100 Marks Model Question Papers

• Bihar Board 12th English 100 Marks Model Question Paper 1 (Science, Commerce)
• Bihar Board 12th English 100 Marks Model Question Paper 2 (Science, Commerce)
• Bihar Board 12th English 100 Marks Model Question Paper 3 (Arts)

Bihar Board 12th English 50 Marks Model Question Papers

• Bihar Board 12th English 50 Marks Model Question Paper 1 (Science, Commerce)
• Bihar Board 12th English 50 Marks Model Question Paper 2 (Science, Commerce)
• Bihar Board 12th English 50 Marks Model Question Paper 3 (Arts)

Bihar Board 12th Intermediate Physics Model Question Papers, Sample Papers 2019, 2020, 2021 with Answers Pdf free download in Hindi Medium and English Medium.

Bihar Board 12th Intermediate Physics Model Question Papers 2020-2021 Pdf with Answers

Bihar Board 12th Model Papers

Bihar Board 12th Physics Model Question Papers in English Medium

• Bihar Board 12th Physics Model Question Paper 1
• Bihar Board 12th Physics Model Question Paper 2
• Bihar Board 12th Physics Model Question Paper 3
• Bihar Board 12th Physics Model Question Paper 4
• Bihar Board 12th Physics Model Question Paper 5

Bihar Board 12th Physics Model Question Papers in Hindi Medium

• Bihar Board 12th Physics Model Question Paper 1
• Bihar Board 12th Physics Model Question Paper 2
• Bihar Board 12th Physics Model Question Paper 3
• Bihar Board 12th Physics Model Question Paper 4
• Bihar Board 12th Physics Model Question Paper 5

Bihar Board 12th Chemistry Model Papers

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

Time : 3 Hours 15 Min
Full Marks: 70

Instructions for the candidates

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

Objective Type Questions

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

Question 1.
How many types of Crystals are found ?
(a) 2
(b) 6
(c) 4
(d) 3
Answer:
(c) 4

Question 2.
Which of the following bond is found in H₂O (ice)?
(a) Hydorgen bond
(b) Metallic bond
(c) Ionic bond
(d) All
Answer:
(a) Hydorgen bond

Question 3.
One Faraday of electricity is equal to how many coulombs ?
(a) 96500
(b) 96550
(c) 94500
(d) 96000
Answer:
(a) 96500

Question 4.
Inverse of resistance is called ………..
(a) Conductance
(b) Resistance
(c) Good conductor
(d) None
Answer:
(d) None

Question 5.
For strong electrolytes λm ………..
(a) increases on dilution
(b) decreases on dilution
(c) remains constant on dilution
(d) All
Answer:
(a) increases on dilution

Question 6.
Chemisorption is ………..
(a) Irreversible in nature
(b) Reversible in nature
(c) Arises due to Van-der-Waals forces
(d) Depends on nature of the gas
Answer:
(a) Irreversible in nature

Question 7.
Chief ore of Iron is ……..
(a) Magnetite (Fe₃O₄)
(b) Haematite (Fe₂O₃)
(c) Siderite (FeCO₃)
(d) Iron pyrite (FeS₄)
Answer:
(b) Haematite (Fe₂O₃)

Question 8.
Which type of ore can be concentrated by Electromagnetic separation method
(a) Non-magnetic particles
(b) Magnetic particles
(c) Sulphide ores
(d) All the above options
Answer:
(b) Magnetic particles

Question 9.
Copper matte contains :
(a) Cu₂S and Cu₂O
(b) Cu₂S and FeS
(c) CuS₂ and Fe₂O₃
(d) Cu₂S and Cu
Answer:
(b) Cu₂S and FeS

Question 10.
Group 15 of Periodic Table includes Nitrogen and …………..
(a) Oxygen
(b) Phosphorous
(c) Carbon
(d) Argon
Answer:
(b) Phosphorous

Question 11.
d-block elements are also known as …………….
(a) Transition elements
(b) Typical elements
(c) Non-transition elements
(d) Alkali metals
Answer:
(a) Transition elements

Question 12.
d-block elements are also known as ………….
(a) Transition elements
(b) Typical elements
(c) Non-transition elements
(d) Alkali metals
Answer:
(a) Transition elements

Question 13.
Zinc is a ………..
(a) Transition element
(b) Lanthanide
(c) Normal element
(d) Element of s-block
Answer:
(c) Normal element

Question 14.
Mn³⁺ is an oxidising agent because………..
(a) half filled K₂-level
(b) Completely filled e_g level
(c) empty d-orbital
(d) All of the above
Answer:
(a) half filled K₂-level

Question 15.
U.P.A.C name of K₂[Zn(OH)₄] is………..
(a) Potassium tetrahydroxoxincate (II)
(b) Zinc di-hydroxide
(c) Zinc hydroxide potassium
(d) None
Answer:
(d) Racemic mixture

Question 16.
The stereo isomens related to each other as non- super imposable mirror images are called
(a) diastereomers
(b) enantiomers
(c) chiral compound
(d) Racemic mixture
Answer:
(a) diastereomers

Question 17.
Chloroform on treatement with O₂ in presence of light gives ………..
(a) Phosphene
(b) Phosgene
(c) Phosphorescence
(d) Methane
Answer:
(b) Phosgene

Question 18.
Alcohols and Phenols are formed when one of the hydrogen atom of Alkane and Arenes are replaced by which group ?
(a) – Cl
(b) – OH
(c) – CHO
(d) – COOH
Answer:
(b) – OH

Question 19.
Glycerol is a …………..
(a) Monohydric alcohol
(b) Di-hydric alcohol
(c) Trihydric alcohol
(d) Tetrahydric alcohol
Answer:
(c) Trihydric alcohol

Question 20.
Simplest hydroxy derivative of Benzene is ………….
(a) Propanol
(b) Phenol
(c) Benzylal cohol
(d) None
Answer:
(b) Phenol

Question 21.
IUPAC name of the compound

(a) 2, 5-dimethyl Phenol
(b) l-Hydroxy-2-methyl toluene
(c) 1-Hydroxy-2, 3-dimethyl benzene
(d) Hydroxy dimethyl benzene
Answer:
(a) 2, 5-dimethyl Phenol

Question 22.
Chloro-ethane on reacting with ammonia gives …………
(a) Ethanamine
(b) Propanamine
(c) Benzylamine
(d) Ethane nitrile
Answer:
(a) Ethanamine

Question 23.
Amides on reduction with LiAlH₄ ………………
(a) Alkanes
(b) Alkylamines
(c) Alcohols
(d) Acids
Answer:
(b) Alkylamines

Question 24.
IUPAC name of HCOOH is …………..
(a) Ethanoic acid
(b) Formic acid
(c) Methanoic acid
(d) Oxalic acid
Answer:
(c) Methanoic acid

Question 25.
IUPAC name of Oxalic acid is …………..
(a) Metanoic acid
(b) Ethanoic acid
(c) Ethanedioic acid
(d) Benzene
Answer:
(c) Ethanedioic acid

Question 26.
The formula of Methylnitrile is ……………
(a) CH₃NC
(b) CH₃CN
(c) C₂H₅CN
(d) C₂H₅NC
Answer:
(b) CH₃CN

Question 27.
Simple Carboxylic acid are soluble in water due to formation of………………………….
(a) Co-Valent bond
(b) Hydrogen bond
(c) Ionic.hood
(d) None
Answer:
(a) Co-Valent bond

Question 28.
The formula of Fructose is ……………
(a) C₆H₁₂O₆
(b) C₁₂H₂₂O₁₁
(c) C₆H₁₂O₅
(d) C₆hH₆O₆
Answer:
(b) C₁₂H₂₂O₁₁

Question 29.
Carbohydrate that yields three to ten mono­saccharides units on hydrolysis are called ………..
(a) Mono-saccharide
(b) Oligo-saccharide
(c) Poly-saccharide
(d) Di-saccharide
Answer:
(a) Mono-saccharide

Question 30.
Amino acid contains two functional groups, one is – COOH and other is …………
(a) – OH
(b) – NH₃
(c) – NH₂
(d) NH₄
Answer:
(b) – NH₃

Question 31.
Polymers of a-amino acid is called …………….
(a) Protein
(b) Peptines
(c) Peptides
(d) Dipeptides
Answer:
(b) Peptines

Question 32.
Polythene is a polymer of ?
(a) Ethane
(b) Ethene
(c) Ethyne
(d) Propene
Answer:
(b) Ethene

Question 33.
Rubber, Starch, Cellulose and Protein are ……………
(a) Synthetic polymers
(b) Natural Polymers
(c) Semi-Synthetic polymers
(d) None of the above
Answer:
(b) Natural Polymers

Question 34.
Buna- N and Buna- S are the types of ……………….
(a) Natural rubber
(b) Synthetic rubber
(c) Polythene
(d) Bakelite
Answer:
(b) Synthetic rubber

Question 35.
The drug used to reduce fever is known as ………………..
(a) Antacid
(b) Analgesic
(c) Anti-pyretic
(d) Anti-biotic
Answer:
(c) Anti-pyretic

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.

Question 1.
What do you mean by Frenkel’s Defect ?
Answer:
This defect is shown by those ionic solids in which there is a large difference in the size of ions,
e.g. ZnS, AgCl, AgBr, Agl.

Question 2.
What do you mean by an Ideal solution ?
Answer:
Ideal solutions obc, Rault’s law over entire range of concentration. For these solution A_mix H = O and A_mix V = O.
In binary solutions, if A – B interactions are nearly equal to A – A or B – B interactions then it is an ideal solution. Solutions of n -hexane & n-heptane, bromoethane & chloroethane, benzene & toluene, etc., are nearly ideal in behaviour.

Question 3.
Define Osmotic pressure ?
Answer:
The hydrostatic pressure which develops on account of osmosis is called Osmotic pressure or the excess pressure that must be applied on the solution to prevent osmosis is called Osmotic pressure.
Osmotic pressure (π) is directly proportional to molarity (C) of the solution at a given temperature π α C
\(\pi=\mathrm{CRT} \text { or, } \pi=\frac{n_{2}}{\mathrm{V}} \mathrm{RT}\left[\text { where }, \mathrm{C}=\frac{n_{2}}{\mathrm{V}}\right]\)

Question 4.
Why Copper sulphate is not stored in zinc pot ?
Answer:
Zinc is stronger reducing agent than copper. Thus zinc forms zinc sulphate during chemical reaction. Therefore, copper sulphate is not stored in zinc pot.
Zn + CuSO₄ → ZnSO₄ + Cu

Question 5.
In Nernst equation
\(\mathbf{E}=\mathbf{E}^{0}-\frac{\mathbf{R} \mathbf{T}}{\mathbf{n} \mathbf{F}} \mathbf{I n} \frac{[\mathbf{M}]}{\left[\mathbf{M}^{\mathbf{n}+}\right]} \mathbf{R}\)
Answer:
It gives the relation between electrode potential, temperature and concentration of metal Ions.

When T = 298 K, F = 96500 C mol-¹
R = 8.314 J K^-1 & concentration of solid M is taken as unity.

Question 6.
Define Cell Constant ?
Answer:
Cell constant : The quantity l/a is called cell constant where ‘l’ is the distance of two electrodes and ‘a’ is the area of cross section of electrode. It is expressed in the units cm^-1.
\(Cell constant =\frac{\text { Distance between the electodes }}{\text { Area of Cross }-\text { Section }}\)

Question 7.
What are Enzymes ?
Answer:
Enzymes are complex nitrogenous organic compounds. They are usually protein molecules of high molecular mass. These are biochemical catalysts as numerous reactions that occur in the bodies of animals & plants to maintain the life process are catalysed by enzymes.

Question 8.
Why does PH₃ fumes in moist air ?
Answer:
PH₃ reacts with moist air to form impure phosphine, which bums in air and forms dense white smoke of metaphosphoric acid.

Question 9.
Why H₂O is liquid and H₂S is gas at room temperature ?
Answer:
H₂O contains hydrogen bonding but H₂S does not contain hydrogen bonding due to oxygen is more electro­negative than sulphur.

Question 10.
On what ground you will say that, Scandium (Z = 21) is a transition metal ?
Answer:
The last electron of Scandium enters in 7-orbital. It has vacant 7-orbital.
Sc (Z = 21)-Is² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹, due to vacant 7-orbital & entering of last electron scandium is a transition element.

Question 11.
Which Ore is stronger reducing agent Cr²⁺ or Fe²⁺ ? Explain.
Answer:
Cr²⁺ is a stronger reducing agent than Fe²⁺.
This is quite evident form the E° values. E° Cr³⁺/Cr²⁺ = – 0.4/V and E° Fe³⁺/Fe²⁺ = 0.77 V.
Reason : T⁴ → 7³ occurs when Cr²⁺ changes to Cr³⁺ ion while T⁶-) T⁵ takes place when Fe²⁺ gets converted to Fe³⁺ ion. Now d⁴ → 7³ transition is easier as compared to T⁶ → T³ transition. Therefore, Cr²⁺ is a stronger reducing agent than Fe²⁺.

Question 12.
What do you mean by inner-transition elements ?
Answer:
The last electron added to each element is an f- electron. These two series of elements are hence called the inner transition elements (f-block Elements). The two rows of elements at the bottom of the Periodic Table, called the Lanthanoids, Ce (Z = 58) – Lu (Z = 71) & Actinoids, Th (Z = 90) – Lr (Z = 103).

Question 13.
What do you mean by co-ordination number ?
Answer:
Co-ordination number : The number of co­ordinate covalent & covalent bonds formed by the central metal of a complex compound is called co-ordination number of the central metal.
Example : [Ag (NH₃)₂]C1 C.N of Ag⁺ ion is 2.

Question 14.
Define Bidentate Ligand ?
Answer:
Bidentate or didentate Ligands: Ligands which has two donar atoms and has tendency to attach to the central ion through two donar atoms. Examples are

Question 15.
What Aldehyde on oxidation will give ?
Answer:
On oxidation aldehyde gives carboxylic acid

Question 16.
Name one water soluble and one fat soluble Vitamin.
Answer:
(a) Water soluble vitamins – (Vitamin B & C)
(b) Fat-soluble vitamins-(Vitamin A, D, E & K)

Question 17.
Define Molarity and Mole fraction.
Answer:
Molarity (M) : It is defined as the number of moles of solute dissolved in one litre (or one cubic decimetre) of the solution.
\(\text { Molarity }(\mathrm{M})=\frac{\text { Number of moles of solute } \times 1000}{\text { Volume of solution }(\mathrm{m} l)}\)
Molality (m) : It is defined as the number of moles of solute per kilogram of the solvent.
\(\text { Molality }(\mathrm{m})=\frac{\text { Number of mol. of solute } \times 1000}{\text { Mass of solvent }(\mathrm{g})}\)

Question 18.
Differentiate between Condensation and Polymerisation.
Answer:
Condensation : The condensation polymers are formed by repeated condensation reaction between two monomeric units having different bifunctional and trifunctional groups with the elimination of small molecules like water, alcohol, hydrogen chloride etc.
Example : Nylon 6, 6

Polymerisation: The process of formation of polymers from respective monomers is called polymerisation,

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.
Find the order of reaction of the following :
(a) Rate = K[A]^1/2 [B]^3/2
(b) Rate = K[A]^3/2 [B]^-1
Answer:
(a) Rate = K[A]^1/2 [B]^3/2
Therefore order = \(\frac{1}{2}+\frac{3}{2}=\frac{4}{2}=2\)
This is called second order reaction.

(b) Rate = K [A]^3/2 [B]^-1
Therefore, order = \(\frac{3}{2}+(-1)=\frac{3}{2}-1=\frac{3-2}{2}=\frac{1}{2}\)
This is first order of reaction

Question 20.
Write in brief about how Sulphuric acid is manufactured by Contact process ?
Answer.
Sulphuric Acid (H₂SO₄) : It is called the king of chemicals and is one of the most widely used industrial chemicals. Manufacture : Sulphuric acid is manufactured by contact process which involves 3 steps

• Burning of sulphur or sulphide ores in air to produce SO₂
  
• Conversion of SO₂ into SO₃ by reaction with air in the presence of catalyst U₂O_s.
• Absorption of SO₃ in H₂SO₄ to give Oleum (H₂ S₂ O₇)

The key step is the catalytical oxidation of SO₂ with O₂ to give SO₃ in the presence of V₂O₅.

The SO₃ gas is absorbed in concentrate H₂SO₄ to produce Oleum (H₂S₂O₇) which on dilution with water gives H₂SO₄ of desired concentration.
SO₃ + H₂SO₄ → H₂ S₂ O₇ (Oleum)
H₂S₂O₇+ H₂O → 2H₂SO₄ The sulphuric acid obtained by the contact process is 96 – 98% pure.

Question 21.
What happens when.
(i) Concentrated H₂S0₄ is added ict Calcium fluoride and heated ?
(ii) SO₃ is passed through water.
Answer.
(i) When concentrated H₂SO₄ is added to calcium fluoride and heated it gives calcium sulphate (CaSO₄) and hydrogen fluoride (HF)
CaF₂ + H₂SO₄ → CaSO₄ + 2HF

(ii) When SO₃ is passed through water it gives sulphuric acid.
SO₃ + H₂O → H₂SO₄

Question 22.
Write the electronic configuration of the following :
(a) Cr³⁺ (b) Cu⁺ (c) CO²⁺ (d) Fe²⁺ (e)Mn²⁺ [Atomic number of Cr = 24, Cu = 29, Co = 27, Fe = Mn = 25]
Answer.
(a) Cr³⁺ – [Ar] 3d³ 4s°
(b) Cu⁺ – [Ar] 3d¹⁰ 4s°
(c) Co²⁺ – [Ar] 3d⁷ 4s°
(d) Fe²⁺ – [Ar] 3d⁶ 4s°
(e) Mn²⁺ – [Ar] 3d⁵ 4s°

Question 23.
How will you convert the following ?
(a) Methane to Ethane
(b) Ethanol to Ethyl acetate
(c) Metane to Chloroform
(d) Ethanal to Ethanoic acid
(e) Acetic acid to methane
Answer.
(a) Methane to Ethane

(b) Ethanol to Ethyl acetate

(c) Metane to Chloroform

(d) Ethanal to Ethanoic acid

(e) Acetic acid to methane

Question 24.
Write short notes on
(a) Inductive effect
(b) Resonance
Answer.
Inductive effect: It is the process of displacement of electrons along, the chain of carbon atoms due to the presence of a polar covalent bond at one end of the chain. This is a permanent effect.
(a) – I effect: When the atoms or group of atoms of the polar covalent bond is more electro-negative than C, it is said to show -I effect.

(b) + I effect: If the substituent attached to the end of the carbon chain is electron donating, the effect is called + I effect.

Resonance : Molecules having two or more structures due to distribution of electrons but same molecular formula is called resonance.
e.g.Benzene molecule has the following structure.

It is represented by a double headed arrow (<->) between the resonating structure.

Conditions :

• The nuclei in each of the canonical structures must be in the same relative position.
• The resonating structure differ only in the way of distribution of electrons.

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

Bihar Board 12th Physics Model Papers

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, candidates should adhere to the words limit as far as practicable.
4. 15 Minutes of extra time has been allotted 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.

Time : 3 Hours 15 Minute
Total Marks : 70

Objective Type Questions

In the following questions from no. 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.
The force acting between two electrons separated by distance r is proportional to
(a) r (b) r² (c) r^-2 (d) r^-1
Answer:
(c) r^-2

Question 2.
The dimensional formula for electric flux is
(a) [ML² T^-3 l^-1] (b) [ML³ T^-3 l^-1] (c) [ML² T⁺³ l^-1] (d) [ML³ T^-3 l]
Answer:
(b) [ML³ T^-3 l^-1]

Question 3.
The Torque experienced by an electric dipole of electric dipole moment \(\overrightarrow{\mathrm{P}}\) in a uniform field \(\overrightarrow{\mathrm{E}}\) is

Answer:
\(\text { (a) } \overrightarrow{\mathrm{P}} \times \overrightarrow{\mathrm{E}}\)

Question 4.
The work done in moving a unit positive charge through a distance x on an equipotential surface is
(a) xj (b) \(\frac{1}{x} j\) (c) zero (d) x²j
Answer:
(c) zero

Question 5.
The electric field intensity inside a charged hollow spherical conductor is
\((a) \epsilon_{0}
(b) E o \sigma
(c) zero
(d) \frac{\epsilon \circ}{\sigma}\)
Answer:
(c) zero

Question 6.
A conductor of capacity 20 mF is charged to 1000 V. The potential energy of the conductor will be
(a) 20 x 10⁴ J (b) 10⁴ J (c) 20 x 10³ J (d) 10³ J
Answer:
(d) 10³ J

Question 7.
The emf of a cell is measured by
(a) Voltmeter (b) Potentiometer (c) Ammeter (d) Voltameter
Answer:
(b) Potentiometer

Question 8.
Kirchoff’s current rule is related to Principle of conservation of
(a) Momentum (b) Energy (c) Charge (d) Angular momentum
Answer:
(c) Charge

Question 9.
Electron volt (eV) is a measure of
(a) Potential difference (b) Charge (c) Energy (d) Current
Answer:
(c) Energy

Question 10.
The Torque experienced by current carrying loop of magnetic moment \(\overrightarrow{\mathbf{M}}\) placed in a magnetic field \(\overrightarrow{\mathbf{B}}\) is

Answer:
(a)

Question 11.
Resistance of Galvanometer is G. Shunt used to allow 1 % of main current through the Galvanometer is
\((a) \frac{\mathrm{G}}{99}
(b) \frac{\mathrm{G}}{90}
(c) \frac{\mathrm{G}}{100}
(d) \frac{99 \mathrm{G}}{100}\)
Answer:
\(\text { (a) } \frac{\mathrm{G}}{99}\)

Question 12.
A Current is flowing in a circular coil. If the radius of the coil is doubled, then the value of magnetic field intensity at its centre will be
(a) same (b) half (c) double (d) four times
Answer:
(b) half

Question 13.
The working of a Dynamo is based on
(a) heating effect of current (b) electro-magnetic induction (c) induced magnetism (d) induced electricity
Answer:
(b) electro-magnetic induction

Question 14.
Unit of self inductance is
(a) Weber (Wb) (b) Ohm (Ω) (c) Henry (d) Gauss
Answer:
(c) Henry

Question 15.
If N₁ and N₂ are number of turns in primary and secondary coil of a transformer, then
(a) N₁ > N₂ (b) N₂ > N₁ (c) N₁ = N₂ (d) N₁ = 0
Answer:
(b) N₂ > N₁

Question 16.
Power factor of L – R circuit is

Answer:
(b)

Question 17.
The ratio of value of magnetic field at same distance from mid point of a small magnet at its axial and equatorial position is
(a) 2′: 1 \(\text { (b) } 1: \sqrt{2}\) \(\text { (c) } \sqrt{2}: 1\) (d) 1 : 2
Answer:
(a) 2 : 1

Question 18.
The angle of dip at magnetic pole of earth is
(a) 0° (b) 90° (c) 45° (d) 180°
Answer:
(b) 90°

Question 19.
The direction of transmission of the electromagnetic wave is
(a) parallel to \(\overrightarrow{\mathrm{E}}\) (b) parallel to \(\overrightarrow{\mathrm{B}}\) (c) parallel to \(\overrightarrow{\mathrm{B}} \times \overrightarrow{\mathrm{E}}\) (d) parallel to \(\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}\)
Answer:
(d) parallel to \(\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}\)

Question 20.
An air bubble inside water shines due to
(a) refraction (b) reflection (c) total internal reflection (d) diffraction
Answer:
(c) total internal reflection

Question 21.
The equivalent focal length of co-axial contact combination of two lenses of power -15D and +5D will be
(a) -10 cm (b) +10cm (c) -20 cm (d) +20 cm
Answer:
(a) -10 cm

Question 22.
The final image in astronomical telescope is
(a) Real and inverted (b) Virtual and erect (c) Virtual and inverted (d) Real and erect
Answer:
(b) Virtual and erect

Question 23.
Cylindrical lenses are used to correct defect of eye is called
(a) Myopia (b) Hypermetropia (c) Astigmatism (d) Presbyopia
Answer:
(c) Astigmatism

Question 24.
In Rayleigh scattering of light, the intensity of scattered light is proportional to the wave-length X in the form of
\((a) \frac{1}{\lambda^{2}}
(b) \frac{1}{\lambda}
(c) \frac{1}{\lambda^{3}}
(d) \frac{1}{\lambda^{4}}\)
Answer:
\((d) \frac{1}{\lambda^{4}}\)

Question 25.
The colour of a thin film is due to
(a) interference (b) diffråction (c) scattering (d) dispersion
Answer:
(a) interference

Question 26.
Ilrcwstcrs Jaw is
(a) μ = cos i_p
(c) μ = sin i_p
(b) μ = tan i_p
(d) μ = cot i_p
Answer:
(a) μ = cos i_p

Question 27.
The energy of a photon of wave-length λ is
(a) \(\frac{h c}{\lambda}\) (b) \(\frac{h \lambda}{C}\) (c) hcλ (d) \(\frac{\lambda}{\mathrm{hc}}\)
Answer:
(b) \(\frac{h \lambda}{C}\)

Question 28.
Which of the spectral line of hydrogen spectrum lies in visible region?
(a) 50 Hz (b) 25 Hz (c) 100 Hz (d) 200 Hz
Answer:
(a) 50 Hz

Question 29.
Which one of the following is a chargeless particle?
(a) α-partcle (b) β-partcle (c) proton (d) photon
Answer:
(a) α-partcle

Question 30.
The time during which the quantity of any radio¬active material becomes half of its original value is called
(a) Average age (b) Half age (c) Decay constant (d) Time period
Answer:
(b) Half age

Question 31.
The majority charge carrier in /i-type semi¬conductor is
(a) a-partcle (b) electron (c) proton (d) hole
Answer:
(b) electron

Question 32.
In full wave rectification, if input frequency is 50 Hz, then output frequency will be
(a) 50 Hz (b) 25 Hz (c) 100 Hz (d) 200 Hz .
Answer:
(a) 50 Hz

Question 33.
The Boolean – expression for NAND gate is
\(\text { (a) } \overline{A+B}=Y\) (b) A + B = Y \(\text { (c) } \overline{A.B}=Y\) (d) A.B = Y
Answer:
\(\text { (c) } \overline{A.B}=Y\)

Question 34.
Result of conversion of decimal number 15 into Binary will be
(a) (1100)₂ (b) (1001)₂ (c) (1111)₂ (d) (11001)₂
Answer:
(c) (1111)₂

Question 35.
Which frequency range is used in TV transmission?
(a) 30 Hz – 300 Hz (b) 30 KHz – 300 KHz (c) 30 MHz – 300 MHz (d) 30 GHZ – 300 GHz
Answer:
(c) 30 MHz – 300 MHz

Section – II

Non-Objective Type Questions
Short Answer Type Questions

Question nos. from 1 to 18 are short answer type questions. Each question of this category carries 2 marks. Answer any ten (10) questions.

Question 1.
What is Electrostatic Shielding? Give its practical application.
Answer:
Electrostatic Shielding:
The electrostatic shielding is the best way to protect some area in vacuum or in alir from the influence of externd electric field.

The technique of electrostatic shielding is applied basically in designing the cable of television.

Question 2.
Give two factors which affect capacitance of a capacitor.
Answer:
The capacity of a capacitor depends upon the following two factors.
(a) On the surface area of the plate of the capacitor.
(b) Distance between the two plates of the capacitor.

Question 3.
Define current density \(\overrightarrow{\mathrm{J}}\) and write expression for Current density in terms of Drift velocity.
Answer:
Current density The current per unit area of conductor is called Current density. It is denoted by J.
\(\mathrm{J}=\frac{1}{\mathrm{A}}\)

It is a Vector quantity.
S.I. unit Ampere/m²
We know that I = ηAeV_d; \(\mathrm{V}_{\mathrm{d}}=\frac{\mathrm{I}}{\eta \mathrm{Ae}} ; \quad \mathrm{V}_{\mathrm{d}}=\frac{1}{\mathrm{ne}}\)

Question 4.
A wire of 12 Ω resistance is stretched to double its length. Find out the new resistance of the wire.
Answer:
In this position volume remains constant

Question 5.
Explain Ampere’s circuital law.
Answer:
Ampere’s circuital law : It states that the line integral of magnetic field \(\overrightarrow{(B)}\) around any closed path or circuit is equal to μ₀ times of total current (I) threading the closed circuit.
\(\oint \overrightarrow{\mathrm{B}} \cdot \overrightarrow{\mathrm{d} 1}=\mu_{0} \mathrm{I}\)
where μ₀ = permeability of vacuum.

Question 6.
What is Shunt? Explain its uses.
Answer:
Shunt :
It is wire of low resistance, joined in parallel with circuit. The current capacity of pivoted type galvanometer is not very large. When large current passes through the cirucit then its coil may burn. To save them from damage, a low resistance wire is joined in parallel and it is called Shunt.

Uses of Shunt :

• In the protection of coil of Galvanometer
• In the conversion of Galvanometer into Ammeter.

Question 7.
Lenz’s law is the law of conservation of energy. Explain.
Answer:
Lenz’s Law : It states that the induced current produced in a circuit always flows in such a direction that it opposes the change or the cause that produces it.

According to Lenz’s law, the induced emf. opposes the change that produces it. It is this opposition against which we perform mechanical work in causing the change in magnetic flux. So, it is the mechanical energy which is converted into electrical energy. Thus, Lenz’s law is in accordance with the law of conservation of energy.

Question 8.
State two differences betwen the magnetic properties of soft iron and steel.
Answer:
Magnetic properties of steel and soft iron :
Steel have high value of retentivity and high value of coercivity. The area of hystersis loop is large for steel. So, it is used to make permanent magnet.

The soft iron have high retentivity and low coercivity. The area of hysteresis loop is small for soft iron, so it is used to make electro-magnet.

Question 9.
Explain Wattless current.
Answer:
Three properties of electro-magenetic waves :

• The electro-magnetic waves are produced by accelerated charges.
• Electro-magnetic waves do not require any material medium for their propagation.
• The electro-magnetic waves obey the principle of Superposition.

Question 10.
State two main characteristics of electro-magnetic waves.
Answer:

• Electromagnetic waves are emitted by electrically charged particles undergoing acceleration.
• Electromagnetic waves of different frequency are called by different names. Since they have different source and effects no matter.

Question 11.
Two thin convex lenses of power 4D and 6D are placed co-axially at a distance of 20 cm apart. Find the focal length and power of the combination of lenses.
Answer:

Question 12.
Write necessary conditions for Interference?
Answer:
Necessary conditions for Interference of light.

• The two sources should emit the light waves continuously.
• The light waves should be of same wave-length.
• The light waves emitted should preferably be of the same amplitude.
• The two light sources should be very narrow.
• The two sources of light must be very close to each other.

Question13.
Write Truth table and Boolean algebraic expression of OR gate and AND gate.
Answer:
Boolean expressiosn of OR gate A + B = Y
Truth table for OR gate

Boolean expression for AND gate A • B = Y Truth table for AND gate

Question 14.
Write the de-Broglie wave-length of an electron of Kinetic energy E.
Answer:
de-Broglie wave length of an electron :
Let m is mass of electron, e is the charge and it is accelerated with potential v.
Energy of electron E = ev …………………….. (i)

K.E. of electron

where h = Plank” constants.

Question 15.
What is Amplitude Modulation? Explain.
Answer:
Amplitude Modulation When the modulating wave is superimposed on a high-frequency carrier wave in a manner that the frequency of the modulated wave is same as that of the carrier wave but its amplitude is modified in accordance with that of the modulating wave the process is called amplitude modulation.

Question 16.
What will be the value of flux of electric field on a closed surface ABC placed near charges +q₁ +q₂ and -q₃?

Answer:
Total charge inside the closed surface = + q₁ – q₃
total electric flux charge q₂ is outside Φ = \(\frac{q_{1}-q_{3}}{\epsilon_{0}}\) the closed surface.

Question 17.
In going from water to glass will speed of light increase or decrease? Explain.
Answer:
When the light ray passes from water to glass its speed decreases because glass is denser medium in comparision to water. When light ray passes from water to glass its wave length decreases. So, speed of light also decreases.

Question 18.
A particle of mass m and charge q is projected with velocity \(\overrightarrow{\mathrm{v}}\) perpendicular to a uniform magnetic field \(\overrightarrow{\mathrm{B}}\). The particle is set in a circular motion. What will be the radius of this circular path?
Answer:
When the charge particle moves perpendicular to magnetic field then its experiences the force F = qBVsinθ
Here θ = 90°; F = qBV ……………………..(i)
when it moves on aircular path then centripetal force
\(F=\frac{m V^{2}}{r}\) …………… (ii)

From equation (i) and (ii)
\(\frac{m v^{2}}{r}=q B V ; m v=q B r ; \quad r=\frac{m v}{q B}\)
This is the expression for radius of circular path.

Long Answer Type Questions

Question nos. from 19 to 24 are long answer type questions. Each question of this category carries 5 marks. Answer any three questions. (3 x 5 = 15)

Question 19.
State Gauss’s law. Applying this law obtain electric field due to an infinitely long thin uniform charged straight wire.
Answer:
Gauss’s Theorem :
It states that the total electric flux through a closed surface enclosing a charge is equal \(\frac{1}{\epsilon_{0}}\) to times the magnitude of charge enclosed.
\(\phi=\frac{q}{\epsilon_{0}}\)

where ε₀ = permitivity of vacuum or air Expression for electric intensity due to infinitely long charged st. wire.

Consider a thin infinitely long st. line charge having a linear charge density λ placed along yy’.

To find electric field due to line charged at point P distance r from it, draw a cylindrical surface of radius r and length l about the line charge as its axis. The cylindrical surface may be treated as the Gaussian surface for the line charge.

If E is the magnitude of electric field at point P, then electric flux through the Gausssian surface is given by
Φ = E x Area of curved surface of cylinder
Φ = E x 2πrl …………………… (i)

According to Gauss’s theorem

Question 20.
Establish the formula for a lens
\(\frac{1}{f}=(\mu-1)\left(\frac{1}{\mathbf{R}_{1}}-\frac{1}{\mathbf{R}_{2}}\right)\)
Answer:
Lens Maker’s Formula :
Suppose L is a thin lens. The refractive index of the material of lens is n₂ and it is placed in a medium of refractive index nx. The optical centre or lens is C and X. X is principal axis. The radii of curvature of the surfaces of the lens are Rj and R₂ and their poles are P₁ and P₂. The thickness of lens is t, which is very small. O is a point object on the principal axis of the lens. The distance of O from pole P₁ is u. The first refracting surface forms the image of O at V at a distance v’ from P₁. From the refraction formula at spherical

The image I acts as a virtual object for second surface and after refraction at second surface, the final image is formed at I. The distance of I from pole P₂ of second surface is v. The distance of virtual object (E) from pole P₂ is (v -1).

For refraction at second surface, the ray is going from second medium (refractive index n₁) to first medium (refractive index (n₂), therefore from refraction formula at spherical surface.
\(\frac{n_{1}}{v}-\frac{n_{2}}{\left(v^{\prime}-1\right)}=\frac{n_{1}-n_{2}}{\mathrm{R}_{2}}\) …………………….. (ii)

For a thin lens t is negligible as compared to v’, therefore from (ii)

where \(\mathrm{l} n_{2}=\frac{n_{2}}{n_{1}}\) is refractive index of second medium (i.e., medium of lens) with respect to first medium.

If the object O is at infinity, the image will be formed at second focus i.e.,

if u = ∞, v = f₂ = f , Therefore from equation (iv)

This is the formula of refraction for a thin lens. This is also called Len’s maker’s formula.

Question 21.
Define Interference of light. Derive an expression for Fringe-Width in Young’s double slits experiment.
Answer:
Interference of Light :
The phenomenon of non-uniform distribution of energy in the medium due to superposition of two light waves is called interference of light.

Expression for Fringe Width :
Consider that two coherent source of light S₁ and S₂ are placed at a distance apart and screen is placed at a distance D from the plane of two source. Let P be a point on the screen at distance y from the centre of screen. If .v is the path difference between light waves reaching point P from the source S₁ and S₂ then x = S₂P – S₁P

Fringe Width :
The spacing between any two consecutive fright fringes is equal to the width of dark frine therefore width of dark fringe.

Thus, in Young’s double slit experiment, the bright and dark fringes are of same width. It is denoted by β.
\(\beta=\frac{D \lambda}{d}\)

Question 22.
State KirchofTs laws. Applying these laws obtain the condition for balanced Wheatstone Bridge.
Answer:
Kirchoff’s law : First law :
In the network of conductor the algebraic sum of current meeting at a point is always zero. It also causes junction rule.

Second law :
It states that in any closed part of an electrical circuit, the algebraic sum of the emf is equal to the algebraic sum of the products of the resistance and current flowing through them. It is also called loop rule. This law is based on the law of conservation of energy.

Wheatstone bridge :
It is one of the accurate arrangements for measuring an unknown resistance. It is based on the principle of Kirchoff s law.

Four resistances P, Q, R and S are connected to form a quadrilateral of galvanometer and a tapping key k₁ (called galvanometer) are connected between points B and D as shown in the figure.

Applying Kirchoff s second law, for closed part ABDA in the circuit I₁ P + I_g g – (I – I₁) S = 0
where g is the resistance of galvanometer In the balanced state I_g = 0

Applying Kirchoff s law in closed part BDCB

From equation (i) and (ii)
\(\frac{P}{S}=\frac{Q}{R}\left[S=\frac{P}{Q} \cdot R\right]\)

Thus unknown resistance can be calculated.

Question 23.
State Biot-Savart law. Applying this law obtain expression of magnetic Held at a point on the axis of a circular coil carrying electric current.
Answer:
Biot-Savart law :
This law establish the relation between magnetic field and current.

Let xy is aonductor in which current I is flowing from v to y. P is the point at the distance r and at this point magnetic field \(\overrightarrow{d B}\) depends upon following factor :

where μ₀ is permeability of vacuum or air.

Magnetic field at the axis of a circular loop :
Consider a circular loop of radius R carrying current I, with its plane perpendicular to the plane of paper. Let P be a point of observation on the axis of this circular loop at a distance x from its centre O. Consider a small element of length dl of the coil at point A. The magnitude of the magnetic induction \(\overrightarrow{\mathrm{dB}}\) at point P due to this element is given by

The direction of \(\overrightarrow{\mathrm{dB}}\) is perpendicular to the plane containing \(\overrightarrow{\mathrm{dl}}\) and \(\overrightarrow{\mathrm{r}}\) is given by Right hand screw rule. As the angle between I \(\overrightarrow{\mathrm{dl}}\) and \(\overrightarrow{\mathrm{r}}\) is 90°, the magnitude of the magnetic induction \(\overrightarrow{\mathrm{dB}}\) is given by,
\(\overrightarrow{d B}=\frac{\mu_{0} I}{4 \pi} \frac{d l \sin 90^{\circ}}{r^{2}}=\frac{\mu_{0} I d l}{4 \pi r^{2}}\)

If we consider the magnetic induction produced by the whole of the circular coil, then by symmetry the components of magnetic induction perpendicular to the axis will be cancelled out, while those parallel to the axis will be added up. Thus the resultant magnetic induction \(\overrightarrow{\mathrm{B}}\) at axial point P is along the axis and may be evaluated as follows :

The component of \(\overrightarrow{\mathrm{dB}}\) along the axis,

Therefore the magnitude of resultant magnetic induction at axial point P due to the whole circular coil is given by

Question 24.
What is Zener diode? Explain its use in a Voltage regulator.
Answer:
Zener diode :
The specially designed Junction diode, which can operate in the reverse breakdown voltage region continuously without being damaged are called Zener diode.

Symbol of Zener diode

Zener diode as a voltage regulator :
The use of Zener diode is based on the fact that in reverse break down region, a very small change in voltage across the Zener diode produces a very large change in the current through the circuit.

If voltage is increased beyond Zener voltage, the resistance of the Zener diode drops considerably. Consider that the Zener diode and a resistance R, called dropping resistor are connected to fluctuating d.c. supply, such that the Zener diode is reverse biased. Whenever voltage across the diode tends to increase, the current through the diode rises out of proportion and causes a sufficient increase in voltage drop across the dropping resistor. As a result, the output voltage lowers back to the normal value. Similarly, when the voltage across the diode tends to decrease, the current through the diode goes down out of proportion, so that the voltage drop across the dropping resistor is much less and now the output voltage is raised to normal.

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