Question 1: Palette 1/178

Allen MCQ

If $10^{6}$ electrons/s are flowing through an area of cross section of $10^{-4}$ m $^{2}$ then the current will be :-

A

$1.6 \times 10^{-7}$ A

B

$1.6 \times 10^{-13}$ A

C

$1 \times 10^{-6}$ A

D

$1 \times 10^{2}$ A

Question 2: Palette 2/178

Allen MCQ

The current in a conductor varies with time t as $I = 2t + 3t^{2}$ A where I is amperes and t in seconds. Electric charge flowing through a section of the conductor during t = 2 s to t = 3 s is :-

A

10 C

B

24 C

C

33 C

D

44 C

Question 3: Palette 3/178

Allen MCQ

10,000 electrons are passing per minute through a tube of radius $1\mathrm{cm}$ . The resulting current is:

A

$10000\mathrm{A}$

B

$0.25 \times 10^{-16}\mathrm{A}$

C

$10^{-9}\mathrm{A}$

D

$0.5 \times 10^{-19}\mathrm{A}$

Question 4: Palette 4/178

Allen MCQ

There are $8.4 \times 10^{22}$ free electrons per cm $^{3}$ in copper. The current in the wire is 0.21 A (e = $1.6 \times 10^{-19}$ C). Then the drifts velocity of electrons in a copper wire of 1 mm $^{2}$ cross section, will be :-

A

$2.12 \times 10^{-5}$ m/s

B

$0.78 \times 10^{-5}$ m/s

C

$1.56 \times 10^{-5}$ m/s

D

none of these

Question 5: Palette 5/178

Allen MCQ

There is a current of 40 amperes in a wire of $10^{-6}\mathrm{m}^2$ area of cross-section. If the number of free electrons per $\mathrm{m}^3$ is $10^{29}$ , then the drift velocity will be

A

$1.25\times 10^{3}\mathrm{m / s}$

B

$2.50\times 10^{-3}\mathrm{m / s}$

C

$25.0\times 10^{-3}\mathrm{m / s}$

D

$250\times 10^{-3}\mathrm{m / s}$

Question 6: Palette 6/178

Allen MCQ

S.I. unit of current is :-

A

C

B

A

C

A/s

D

N/s

Question 7: Palette 7/178

Allen MCQ

When no current flows through a conductor:

A

the free electrons do not move

B

the average speed of a free electron over a large period of time is zero

C

the average velocity of a free electron over a large period of time is zero

D

the average of square of velocities of all the free electrons at an instant is zero

Question 8: Palette 8/178

Allen MCQ

The number of free electrons per 10 mm of an ordinary copper wire is about $2 \times 10^{21}$ . The average drift speed of the electrons is 0.25 mm/s. The current flowing is:-

A

0.8 A

B

8 A

C

80 A

D

5 A

Question 9: Palette 9/178

Allen MCQ

In a Neon discharge tube $2.9 \times 10^{18}$ Ne $^{+}$ ions move to the right each second, while $1.2 \times 10^{18}$ electrons move to the left per second; electron charge is $1.6 \times 10^{-19}$ C. The current in the discharge tube is :-

A

1 A towards right

B

0.66 A towards right

C

0.66 A towards left

D

zero

Question 10: Palette 10/178

Allen MCQ

Two wires each of radius of cross section r but of different materials are connected together end to end (in series). If the densities of charge carriers in the two wires are in the ratio 1:4, the drift velocity of electrons in the two wires will be in the ratio:

A

1 : 2

B

2 : 1

C

4 : 1

D

1 : 4

Question 11: Palette 11/178

Allen MCQ

A current I flows through a uniform wire of diameter d when the electron drift velocity is v. The same current will flow through a wire of diameter d/2 made of the same material if the drift velocity of the electrons is

A

v/4

B

v/2

C

2v

D

4v

Question 12: Palette 12/178

Allen MCQ

A wire has a non-uniform cross-section as shown in figure. A steady current flows through it. The drift speed of electrons at points P and Q is $v_{P}$ and $v_{Q}$ , then :-

A

$\mathrm{v_P} = \mathrm{v_Q}$

B

$\mathrm{v_P} < \mathrm{v_Q}$

C

$\mathrm{V_P > V_Q}$

D

data is insufficient

Question 13: Palette 13/178

Allen MCQ

The plot represents the flow of current through a wire for different time intervals. The ratio of charges flowing through the wire corresponding to these time intervals is (see figure) :-

A

2 : 1 : 2

B

1 : 3 : 3

C

1 : 1 : 1

D

2 : 3 : 4

Question 14: Palette 14/178

Allen MCQ

Three copper wires are there with lengths and cross-sectional areas as $(\ell, A)$ ; $\left(2\ell, \frac{A}{2}\right)$ and $\left(\frac{\ell}{2}, 2A\right)$ . Resistance:

A

minimum for the wire of cross-sectional are $\frac{A}{2}$

B

minimum for the wire of cross-sectional are $A$

C

minimum for the wire of cross-sectional area $2A$

D

same for all the three cases.

Question 15: Palette 15/178

Allen MCQ

A wire of uniform cross-section A, length ℓ and resistance R is bent into a complete circle; the resistance between any two of diametrically opposite points will be:-

A

$\frac{R}{2}$

B

$\frac{R}{4}$

C

$\frac{R}{8}$

D

4R

Question 16: Palette 16/178

Allen MCQ

The electric resistance of a certain wire of iron is R. If its length and radius both are doubled, then:-

A

the resistance will be halved and the specific resistance will remain unchanged

B

the resistance will be halved and the specific resistance will be doubled

C

the resistance and the specific resistance, will both remain unchanged

D

the resistance will be doubled and the specific resistance will be halved.

Question 17: Palette 17/178

Allen MCQ

When a piece of aluminium wire of finite length is drawn to reduce its diameter to half its original value, its resistance will become :

A

two times

B

four times

C

eight times

D

sixteen times

Question 18: Palette 18/178

Allen MCQ

As the temperature of a metallic resistor is increased, the product of resistivity and conductivity :-

A

increases

B

decreases

C

may increase or decrease

D

remains constant.

Question 19: Palette 19/178

Allen MCQ

If a wire is stretched, so that its length is 20% more than its initial length, the percentage increase in the resistance of the wire is :-

A

40%

B

10%

C

44%

D

25%

Question 20: Palette 20/178

Allen MCQ

The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be:-

A

300%

B

200%

C

100%

D

50%

Question 21: Palette 21/178

Allen MCQ

On increasing the temperature, the specific resistance of a conductor and a semiconductor-

A

both increase

B

both decrease

C

increases and decreases respectively

D

decreases and increases respectively

Question 22: Palette 22/178

Allen MCQ

A conductor with rectangular cross section has dimensions $(a \times 2a \times 4a)$ as shown in figure. Resistance across AB is x, across CD is y and across EF is z. Then

A

$x = y = z$

B

$x > y > z$

C

$y > x > z$

D

$x > z > y$

Question 23: Palette 23/178

Allen MCQ

Specific resistance of a conductor increases with:-

A

increase in temperature.

B

increase in cross-sectional area

C

increase in cross-sectional area and decrease in length.

D

decrease in cross-sectional area.

Question 24: Palette 24/178

Allen MCQ

The temperature coefficient of resistance of a wire is 0.00125 per degree celcius. At 300 K its resistance is 1 ohm. The resistance of the wire will be 2 ohms at a temperature:-

A

1154 K

B

1127 K

C

600 K

D

1400 K

Question 25: Palette 25/178

Allen MCQ

The current voltage graph for a given metallic conductor at two different temperatures $T_{1}$ and $T_{2}$ are as shown in the figure. Then :-

A

$\mathrm{T}_{1} > \mathrm{T}_{2}$

B

$\mathrm{T}_{1} = \mathrm{T}_{2}$

C

nothing can be said about $\mathrm{T}_{1}$ and $\mathrm{T}_{2}$

D

$\mathrm{T}_{1} < \mathrm{T}_{2}$

Question 26: Palette 26/178

Allen MCQ

The effective resistance is $\frac{6}{5}\Omega$ , when two wires are joined in parallel. When one of the wire breaks, the effective resistance is 2 ohms. The resistance of the broken wire was:-

A

$\frac{3}{5}\Omega$

B

$2\Omega$

C

$\frac{6}{5}\Omega$

D

$3\Omega$

Question 27: Palette 27/178

Allen MCQ

At what temperature will the resistance of a copper wire become three times its value at $0^{\circ}$ C? [Temperature coefficient of resistance for copper = $4 \times 10^{-3}$ per ${}^{\circ}$ C] :-

A

$400^{\circ}$ C

B

$450^{\circ}$ C

C

$500^{\circ}$ C

D

$600^{\circ}$ C

Question 28: Palette 28/178

Allen MCQ

Copper and silicon are cooled from 300 K to 60 K; the specific resistance:-

A

decreases in copper but increases in silicon

B

increases in copper but decreases in silicon

C

increases in both

D

decreases in both

Question 29: Palette 29/178

Allen MCQ

Two resistances $R_{1}$ and $R_{2}$ are made of different materials. The temperature coefficient of the material of $R_{1}$ is $\alpha$ and that of the material of $R_{2}$ is $-\beta$ . The resistance of the series combination of $R_{1}$ and $R_{2}$ does not change with temperature, then the ratio of resistances of the two wires at $0^{\circ}C$ will be:

A

$\frac{\alpha}{\beta}$

B

$\frac{\alpha + \beta}{\alpha - \beta}$

C

$\frac{\alpha^{2} + \beta^{2}}{\alpha\beta}$

D

$\frac{\beta}{\alpha}$

Question 30: Palette 30/178

Allen MCQ

A metal wire of resistance R is cut into three equal pieces which are then connected side by side to form a new wire, the length of which is equal to one third of the original length. The resistance of this new wire is:-

A

R

B

3R

C

$\frac{R}{9}$

D

$\frac{R}{3}$

Question 31: Palette 31/178

Allen MCQ

Three resistances of values 2 Ω, 3 Ω and 6 Ω are to be connected to yield an effective resistance of 4 Ω. This can be done by connecting:

A

3 Ω resistance in series with a parallel combination of 2 Ω and 6 Ω

B

6 Ω resistance in series with a parallel combination of 2 Ω and 3 Ω

C

2 Ω resistance in series with a parallel combination of 3 Ω and 6 Ω

D

2 Ω resistance in parallel with a parallel combination of 3 Ω and 6 Ω

Question 32: Palette 32/178

Allen MCQ

What will be the equivalent resistance between the points A and D? A 10 Ω 10 Ω 10 Ω B C 10 Ω 10 Ω 10 Ω D

A

10 Ω

B

20 Ω

C

30 Ω

D

40 Ω

Question 33: Palette 33/178

Allen MCQ

In the circuit shown here, what is the value of the unknown resistance R so that the total resistance of the circuit between points 'P' and 'Q' is also equal to R :-

A

$\ 3\Omega$

B

$\ \sqrt{39}\Omega$

C

$\ \sqrt{69}\Omega$

D

$\ 10\Omega$

Question 34: Palette 34/178

Allen MCQ

The resistance across P and Q in the given figure is

A

$\frac{\mathrm{R}}{3}$

B

$\frac{\mathrm{R}}{2}$

C

$2\mathrm{R}$

D

$6\mathrm{R}$

Question 35: Palette 35/178

Allen MCQ

The resistance of the circuit between A and B is :

A

r

B

0.5r

C

2r

D

3r

Question 36: Palette 36/178

Allen MCQ

Thirteen resistances each of resistance R $\Omega$ are connected in the circuit as shown in the figure. The effective resistance between A and B is :-

A

$\frac{4\mathrm{R}}{3}\Omega$

B

$2\mathrm{R}\Omega$

C

$\mathrm{R}\Omega$

D

$\frac{2\mathrm{R}}{3}\Omega$

Question 37: Palette 37/178

Allen MCQ

The total resistance between x and y in ohms is:-

A

$1\Omega$

B

$4\Omega$

C

$\frac{4}{3}\Omega$

D

$\frac{2}{3}\Omega$

Question 38: Palette 38/178

Allen MCQ

The resultant resistance of n wires each of resistance r ohms is R, when they are connected in parallel. When these n resistances are connected in series, the resultant resistance will be :-

A

$\frac{R}{n}$

B

$\frac{R}{n^{2}}$

C

nR

D

$n^{2}R$

Question 39: Palette 39/178

Allen MCQ

For the network of resistance shown in the fig. the equivalent resistance of the network between the points A and B is 18 Ω. The value of unknown resistance R is :-

A

8 $\Omega$

B

10 $\Omega$

C

16 $\Omega$

D

24 $\Omega$

Question 40: Palette 40/178

Allen MCQ

In the arrangement of resistances shown below, the effective resistance between points A and B is

A

20 $\Omega$

B

30 $\Omega$

C

90 $\Omega$

D

110 $\Omega$

Question 41: Palette 41/178

Allen MCQ

In the circuit shown the equivalent resistance between A and B is

A

R

B

2R/5

C

R/3

D

2R

Question 42: Palette 42/178

Allen MCQ

In the figure the numerical values denote resistances in SI units. The total resistance of the circuit between a & b will be:

A

12 ohms

B

24 ohms

C

15 ohms

D

6 ohms

Question 43: Palette 43/178

Allen MCQ

Resistors $R_{1}$ and $R_{2}$ have an equivalent resistance of 6 ohms when connected in the circuit shown below. The resistance of $R_{1}$ could be (in $\Omega$ ):

A

1

B

5

C

8

D

4

Question 44: Palette 44/178

Allen MCQ

Value of current i in the following circuit is :-

A

13 A

B

$12 \mathrm{~A}$

C

9 A

D

none of the above

Question 45: Palette 45/178

Allen MCQ

The potential difference between X and Y in volts is :-

A

1

B

-1

C

2

D

-2

Question 46: Palette 46/178

Allen MCQ

If each resistance in the fig. is of 9 Ω then reading of the ammeter is :-

A

5 A

B

8 A

C

2 A

D

9 A

Question 47: Palette 47/178

Allen MCQ

If i = 0.25 A in figure, then value of R is :-

A

$48\Omega$

B

$12\Omega$

C

$120\Omega$

D

$42\Omega$

Question 48: Palette 48/178

Allen MCQ

If the ammeter in the given circuit reads 2 A, the resistance R is :-

A

1 ohms

B

2 ohms

C

3 ohms

D

4 ohms

Question 49: Palette 49/178

Allen MCQ

The equivalent resistance and potential difference between A and B for the circuit are respectively :-

A

$4\Omega ,8\mathrm{V}$

B

$8\Omega ,4\mathrm{V}$

C

$2\Omega ,2\mathrm{V}$

D

$16\Omega ,8\mathrm{V}$

Question 50: Palette 50/178

Allen MCQ

For the current loops shown in the figure, Kirchhoff's loop rule for the loops AHDCBA and AHDEFGA yields these equations respectively :-

A

$-30\mathrm{I}_1 - 41\mathrm{I}_3 + 45 = 0$ and $-30\mathrm{I}_1 + 21\mathrm{I}_2$ $-80 = 0$

B

$30\mathrm{I}_1 - 41\mathrm{I}_3 + 45 = 0$ and $30\mathrm{I}_1 - 21\mathrm{I}_2 - 80 = 0$

C

$30\mathrm{I}_1 + 41\mathrm{I}_3 - 45 = 0$ and $-30\mathrm{I}_1 + 21\mathrm{I}_2$ $+80 = 0$

D

$-30\mathrm{I}_1 - 41\mathrm{I}_3 - 45 = 0$ and $-30\mathrm{I}_1 + 21\mathrm{I}_2$ $-80 = 0$

Question 51: Palette 51/178

Allen MCQ

In the circuit shown in figure, find the current through the branch BD.

A

$1\mathrm{A}$

B

$5\mathrm{A}$

C

$3\mathrm{A}$

D

$7\mathrm{A}$

Question 52: Palette 52/178

Allen MCQ

In the circuit shown below, the reading of the voltmeter V is :-

A

$12\mathrm{V}$

B

$8\mathrm{V}$

C

$20\mathrm{V}$

D

$16\mathrm{V}$

Question 53: Palette 53/178

Allen MCQ

Find the potential of J with respect of G :-

A

$40\mathrm{V}$

B

$60\mathrm{V}$

C

$20\mathrm{V}$

D

$30\mathrm{V}$

Question 54: Palette 54/178

Allen MCQ

Find the potential difference across the $24 \Omega$ :

A

48 volts

B

2 volts

C

4 volts

D

1 volts

Question 55: Palette 55/178

Allen MCQ

In a network as shown in the figure the potential difference across the resistance 2R is (the cell has an emf E with no internal resistance):

A

$2\mathrm{E}$

B

$\frac{4\mathrm{E}}{7}$

C

$\frac{\mathrm{E}}{7}$

D

E

Question 56: Palette 56/178

Allen MCQ

The reading of ammeter is $I_{1}$ when only $S_{1}$ is closed and $I_{2}$ when only $S_{2}$ is closed. The reading is $I_{3}$ when both $S_{1}$ & $S_{2}$ are closed simultaneously then :-

A

$\mathrm{I}_1 > \mathrm{I}_2 > \mathrm{I}_3$

B

$\mathrm{I}_2 > \mathrm{I}_3 > \mathrm{I}_1$

C

$\mathrm{I}_3 > \mathrm{I}_2 > \mathrm{I}_1$

D

$\mathrm{I}_3 > \mathrm{I}_1 > \mathrm{I}_2$

Question 57: Palette 57/178

Allen MCQ

How will the reading of ammeter change if the key k is closed?

A

Increase

B

Decrease

C

Remains same

D

Information insufficient

Question 58: Palette 58/178

Allen MCQ

Six resistors each of $10 \Omega$ are connected as shown. The equivalent resistance between points X and Y is :

A

$20\Omega$

B

$5\Omega$

C

$25 / 3\Omega$

D

$10\Omega$

Question 59: Palette 59/178

Allen MCQ

Five equal resistances each of resistance R are connected as shown in the Figure. A battery of voltage V is connected between A and B. The current flowing in AFCEB will be

A

$\frac{\mathrm{V}}{\mathrm{R}}$

B

$\frac{\mathrm{V}}{2\mathrm{R}}$

C

$\frac{2\mathrm{V}}{\mathrm{R}}$

D

$\frac{3\mathrm{V}}{\mathrm{R}}$

Question 60: Palette 60/178

Allen MCQ

In a typical Wheatstone bridge the resistance in cyclic order are $A = 10 \Omega$ , $B = 5 \Omega$ , $C = 4\Omega$ and $D = 4 \Omega$ . For the bridge to be balanced :

(a) 10 Ω should be connected in parallel with A
(b) 10 Ω should be connected in series with A
(c) 5 Ω should be connected in series with B
(d) 5 Ω should be connected in parallel with B

A

a, b

B

b, c

C

a, c

D

all

Question 61: Palette 61/178

Allen MCQ

Seven resistances are connected as shown in the figure. The equivalent resistance between A and B is :-

A

3 Ω

B

4 Ω

C

4.5 Ω

D

5 Ω

Question 62: Palette 62/178

Allen MCQ

In the following circuit diagram the value of resistance X for the potential difference between B and D to be zero is :-

A

4 ohms

B

6 ohms

C

56 ohms

D

9 ohms

Question 63: Palette 63/178

Allen MCQ

In the arrangement of resistances shown in the circuit, the potential difference between points B and D will be zero, when the unknown resistance X is :-

A

4 Ω

B

3 Ω

C

2 Ω

D

1 Ω

Question 64: Palette 64/178

Allen MCQ

The resistance of each arm of a Wheat stone bridge is 10 Ω. A resistance of 10 Ω is connected in series with the galvanometer then the equivalent resistance across the battery will be :-

A

10 Ω

B

15 Ω

C

20 Ω

D

40 Ω

Question 65: Palette 65/178

Allen MCQ

For the network shown in the figure the value of the current i is :-

A

$\frac{18\mathrm{V}}{5}$

B

$\frac{5\mathrm{V}}{9}$

C

$\frac{9\mathrm{V}}{35}$

D

$\frac{5\mathrm{V}}{18}$

Question 66: Palette 66/178

Allen MCQ

Two cells X and Y are connected to a resistance of $10 \Omega$ as shown in the figure. The terminal voltage of cell Y is :-

A

zero

B

$2\mathrm{V}$

C

$4\mathrm{V}$

D

$10\mathrm{V}$

Question 67: Palette 67/178

Allen MCQ

A battery has e.m.f. 4 V and internal resistance 'r'. When this battery is connected to an external resistance of 2 ohms, a current of 1 A flows in the circuit. What current will flow if the terminals of the battery are connected directly?

A

1 A

B

2 A

C

4 A

D

infinite

Question 68: Palette 68/178

Allen MCQ

Internal resistance of primary cell depends on :-

A

the nature of electrolyte

B

the area of plates immersed in the electrolyte

C

the concentration of electrolyte and distance between the plates

D

all the above

Question 69: Palette 69/178

Allen MCQ

The potential difference between the terminals of a cell is found to be 3 volts when it is connected to a resistance of value equal to its internal resistance. The e.m.f. of the cell is:

A

3 V

B

6 V

C

1.5 V

D

4.5 V

Question 70: Palette 70/178

Allen MCQ

A current of 2 A is flowing through a cell of e.m.f. 5 V and internal resistance 0.5 Ω from negative to positive electrode. If the potential of negative electrode is 10 V, the potential of positive electrode will be :-

A

5 V

B

14 V

C

15 V

D

16 V

Question 71: Palette 71/178

Allen MCQ

In the following circuit if $V_{A}-V_{B}=4V$ , then the value of resistance X in ohms will be :-

A

5

B

10

C

15

D

20

Question 72: Palette 72/178

Allen MCQ

Electromotive force of a cell is basically a

A

force

B

power

C

work

D

current capacity

Question 73: Palette 73/178

Allen MCQ

The terminal voltage is $\frac{E}{2}$ when a current of 2 A is flowing through 2 Ω resistance; the internal resistance of the cell is:-

A

1 Ω

B

2 Ω

C

3 Ω

D

4 Ω

Question 74: Palette 74/178

Allen MCQ

When a resistance of 2 ohms is connected across the terminals of a cell, the current is 0.5 A. When the resistance is increased to 5 ohms, the current becomes 0.25 A. The e.m.f. of the cell is:-

A

1.0 V

B

1.5 V

C

2.0 V

D

2.5 V

Question 75: Palette 75/178

Allen MCQ

A cell of e.m.f. 2 V and negligible internal resistance is connected to resistors $R_{1}$ and $R_{2}$ as shown in the figure. The resistance of the voltmeter, $R_{1}$ and $R_{2}$ are 80 Ω, 40 Ω and 80 Ω respectively. The reading of the voltmeter is :

A

$1.78\mathrm{V}$

B

$1.60\mathrm{V}$

C

$0.80\mathrm{V}$

D

$1.33\mathrm{V}$

Question 76: Palette 76/178

Allen MCQ

A cell supplies a current of 0.9 A through a 2 Ω resistor and a current of 0.3 A through a 7 Ω resistor. The internal resistance of the cell is:

A

1.0 Ω

B

0.5 Ω

C

2.0 Ω

D

1.2 Ω

Question 77: Palette 77/178

Allen MCQ

A 10 V battery with internal resistance 0.5 Ω is connected across a variable resistance R. The value of R for which the power delivered to it is maximum, is equal to

A

0.5 Ω

B

1 Ω

C

1.5 Ω

D

2 Ω

Question 78: Palette 78/178

Allen MCQ

An electric bulb is designed to draw a power $P_{0}$ at voltage $V_{0}$ . If the voltage is V, it draws a power P, then -

A

$P = \left( \frac{V}{V_{0}} \right) P_{0}$

B

$P = \left( \frac{V_{0}}{V} \right) P_{0}$

C

$P = \left( \frac{V_{0}}{V} \right)^{2} P_{0}$

D

$P = \left( \frac{V}{V_{0}} \right)^{2} P_{0}$

Question 79: Palette 79/178

Allen MCQ

Consider the four circuits shown in the figure below. In which circuit power dissipated maximum (Neglect the internal resistance of the power supply)

A

B

C

D

Question 80: Palette 80/178

Allen MCQ

Three resistances of equal value are arranged in different combinations as shown below. Arrange them in the increasing order of power dissipation:
(I)

(II)

(III)

(IV)

A

III < II < IV < I

B

II < III < IV < I

C

I < IV < III < II

D

I < III < II < IV

Question 81: Palette 81/178

Allen MCQ

25 W, 200 V and 100 W, 200 V bulbs are connected in series to a source of 400 volts. Which bulb will fuse?

A

25 W

B

100 W

C

Both will fuse at the same time

D

None of the bulbs will fuse

Question 82: Palette 82/178

Allen MCQ

You are provided with 48 cells, each of emf 2 volts and internal resistance 4 ohms. What maximum current can flow in the circuit having an external resistance of $12\Omega$ ?

A

1 A

B

1.2 A

C

0.96 A

D

1.08 A

Question 83: Palette 83/178

Allen MCQ

Two electric bulbs of the same power, but with different marked voltages are connected in series across a power line. Their brightness will be :-

A

directly proportional to their marked voltages

B

inversely proportional to their marked voltages

C

directly proportional to the squares of their marked voltages

D

inversely proportional to the squares of their marked voltages

Question 84: Palette 84/178

Allen MCQ

Four circuits are shown below. All the batteries have the same voltage V and all resistors have the same resistance R. In which circuit does the battery delivers the most power?

A

B

C

D

Question 85: Palette 85/178

Allen MCQ

Two cells, each of e.m.f. E and internal resistance r, are connected in parallel across a resistor R. The power dissipated in the resistor is maximum if:

A

R = r

B

R = 2r

C

$R = \frac{3r}{2}$

D

$R = \frac{r}{2}$

Question 86: Palette 86/178

Allen MCQ

In the circuit shown in figure, the power which is dissipated as heat in the $6 \Omega$ resistor is 6 W. What is the value of resistance R in the circuit?

A

$6\Omega$

B

$10\Omega$

C

$13\Omega$

D

$24\Omega$

Question 87: Palette 87/178

Allen MCQ

For different values of resistance, R power consumptions in R are given. Then which of the following values are not possible?

(a) 2 W (b) 5 W (c) 8 W (d) 4 W

A

Only c

B

b & c

C

a, b, c

D

All

Question 88: Palette 88/178

Allen MCQ

An ammeter and a voltmeter are joined in series to a cell. Their readings are A and V respectively. If a resistance is now joined in parallel with the voltmeter

A

both A and V will decrease

B

both A and V will increase

C

A will increase, V will decrease

D

A will decrease, V will increase

Question 89: Palette 89/178

Allen MCQ

A galvanometer of 100 Ω resistance yields complete deflection when 10 mA current flows. What should be the value of shunt so that it can measure currents upto 100 mA?

A

11.11 Ω

B

9.9 Ω

C

1.1 Ω

D

4.4 Ω

Question 90: Palette 90/178

Allen MCQ

In order to change the range of a galvanometer of G Ω resistance from V volts to nV volts what will be the value of resistance in Ω connected in series with it:-

A

(n-1)G

B

$\frac{G}{n}$

C

nG

D

$\frac{G}{n-1}$

Question 91: Palette 91/178

Allen MCQ

Resistance in the two gaps of a meter bridge are 10 ohms and 30 ohms respectively. If the resistances are interchanged, the balance point shifts by :-

A

33.3 cm

B

66.67 cm

C

25 cm

D

50 cm

Question 92: Palette 92/178

Allen MCQ

A galvanometer acting as a voltmeter will have :

A

a high resistance in series with its coil

B

a low resistance in parallel with its coil

C

a low resistance in series with its coil

D

a high resistance in parallel with its coil

Question 93: Palette 93/178

Allen MCQ

In the shown arrangement of the experiment of a meter bridge if AC, corresponding to null deflection of galvanometer, is x then what would be its value if the radius of the wire AB is doubled:-

A

x

B

$\frac{\mathrm{x}}{4}$

C

$4\mathrm{x}$

D

$2\mathrm{x}$

Question 94: Palette 94/178

Allen MCQ

In the following circuit, the resistance of the voltmeter is 10,000 Ω and that of the ammeter is 20 Ω. If the reading of the ammeter is 0.1 A and that of the voltmeter is 12 V, then the value of R is :-

A

$122\Omega$

B

$100\Omega$

C

$118\Omega$

D

$116\Omega$

Question 95: Palette 95/178

Allen MCQ

The resistance of a galvanometer is G ohms and the range is 1 volt. The value of resistance (in $\Omega$ ) used to convert it into a voltmeter of range 10 volts is :-

A

9 G

B

G

C

$\frac{1}{9}$ G

D

10 G

Question 96: Palette 96/178

Allen MCQ

A galvanometer has 36 Ω resistance. If a 4 Ω shunt is added to this, the fraction of current that passes through the galvanometer is :-

A

$\frac{1}{4}$

B

$\frac{1}{9}$

C

$\frac{1}{10}$

D

$\frac{1}{40}$

Question 97: Palette 97/178

Allen MCQ

A galvanometer of resistance 100 Ω gives full deflection for a current of $10^{-5}$ A. The value of shunt required to convert it into an ammeter of range 1 ampere, is :-

A

1 Ω

B

$10^{-3}$ Ω

C

$10^{-5}$ Ω

D

100 Ω

Question 98: Palette 98/178

Allen MCQ

There are three voltmeters of the same range but of resistances 10000 Ω, 8000 Ω and 4000 Ω respectively. The best voltmeter among these is the one whose resistance is :-

A

10000 Ω

B

8000 Ω

C

4000 Ω

D

all are equally good

Question 99: Palette 99/178

Allen MCQ

20% of the main current passes through the galvanometer. If the resistance of the galvanometer is G, then the resistance of the shunt will be :-

A

$\frac{G}{50}$

B

$\frac{G}{4}$

C

$50G$

D

$9G$

Question 100: Palette 100/178

Allen MCQ

An unknown resistance $R_{1}$ is connected in series with a resistance of 10 Ω. This combination is connected to one gap of a metre bridge while a resistance $R_{2}$ is connected in the other gap. The balance point is at 50 cm. Now, when the 10 Ω resistance is removed the balance point shifts to 40 cm. The value of $R_{1}$ is (in ohms) :-

A

20

B

10

C

60

D

40

Question 101: Palette 101/178

Allen MCQ

A 1 Ω voltmeter has a range of 1V. Find the additional resistance which has to be joined with the series in voltmeter to increase the range of voltmeter to 100 V:

A

10 Ω

B

$\frac{1}{99}$ Ω

C

99 Ω

D

100 Ω

Question 102: Palette 102/178

Allen MCQ

A galvanometer having a resistance G and current $i_{a}$ flowing in it, produces full scale deflection. If $S_{1}$ is the value of shunt which converts it into an ammeter of range 0 - i and $S_{2}$ is the value of the shunt for the range 0 - 2i. Then the ratio $\frac{S_{1}}{S_{2}}$ will be :-

A

1

B

2

C

$\frac{1}{2}\left(\frac{i-i_{a}}{2i-i_{a}}\right)$

D

$\left(\frac{2i-i_{a}}{i-i_{a}}\right)$

Question 103: Palette 103/178

Allen MCQ

Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volts and the average resistance per km is 0.5 Ω. the power loss in the wires is :-

A

19.2 W

B

19.2 kW

C

19.2 J

D

12.2 kW

Question 104: Palette 104/178

Allen MCQ

The resistance in the two arms of a meter bridge are 5 Ω and R Ω, respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6 ℓ₁. The resistance ‘R’ is :-

A

$10 \Omega$

B

$15 \Omega$

C

$20 \Omega$

D

$25 \Omega$

Question 105: Palette 105/178

Allen MCQ

In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, then resistance of ammeter will be :-

A

$\frac{1}{499}G$

B

$\frac{499}{500}G$

C

$\frac{1}{500}G$

D

$\frac{500}{499}G$

Question 106: Palette 106/178

Allen MCQ

Two metal wires of identical dimensions are connected in series. If $\sigma_{1}$ and $\sigma_{2}$ are the conductivities of the metal wires respectively, the effective conductivity of the combination is :-

A

$\frac{\sigma_{1}\sigma_{2}}{\sigma_{1} + \sigma_{2}}$

B

$\frac{2\sigma_{1}\sigma_{2}}{\sigma_{1} + \sigma_{2}}$

C

$\frac{\sigma_{1} + \sigma_{2}}{2\sigma_{1}\sigma_{2}}$

D

$\frac{\sigma_{1} + \sigma_{2}}{\sigma_{1}\sigma_{2}}$

Question 107: Palette 107/178

Allen MCQ

A circuit contains an ammeter, a battery of 30 V and a resistance 40.8 ohm all connected in series. If the ammeter has a coil of resistance 480 ohm and a shunt of 20 ohm, the reading in the ammeter will be :-

A

$1\mathrm{A}$

B

$0.5\mathrm{A}$

C

$0.25\mathrm{A}$

D

$2\mathrm{A}$

Question 108: Palette 108/178

Allen MCQ

Across a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is:

A

current

B

drift velocity

C

electric field

D

current density

Question 109: Palette 109/178

Allen MCQ

A, B and C are voltmeters of resistance R, 1.5 R and 3R respectively as shown in the figure. When some potential difference is applied between X and Y, the voltmeter readings are $V_{A}$ , $V_{B}$ and $V_{C}$ respectively. Then :

A

$\mathrm{V_A}\neq \mathrm{V_B} = \mathrm{V_C}$

B

$\mathrm{V_A} = \mathrm{V_B}\neq \mathrm{V_C}$

C

$\mathrm{V_A}\neq \mathrm{V_B}\neq \mathrm{V_C}$

D

$\mathrm{V_A} = \mathrm{V_B} = \mathrm{V_C}$

Question 110: Palette 110/178

Allen MCQ

The potential difference (V_A - V_B) between the points A and B in the given figure is :- (A) I=2A 2Ω +3V - 1Ω V_B B

A

+6V

B

+9V

C

-3V

D

+3V

Question 111: Palette 111/178

Allen MCQ

A filament bulb (500 W, 100 V) is to be used in a 230 V main supply. When a resistance R is connected in series, it works perfectly and the bulb consumes 500 W. The value of R is :-

A

26 Ω

B

13 Ω

C

230 Ω

D

46 Ω

Question 112: Palette 112/178

Allen MCQ

The resistance of a wire is 'R' ohm. If it is melted and stretched to 'n' times its original length, its new resistance will be :-

A

$\frac{R}{n}$

B

$n^{2}R$

C

$\frac{R}{n^{2}}$

D

nR

Question 113: Palette 113/178

Allen MCQ

A set of 'n' equal resistors, of value 'R' each, are connected in series to a battery of emf 'E' and internal resistance 'R'. The current drawn is I. Now, the 'n' resistors are connected in parallel to the same battery. Then the current drawn from battery becomes 10 I. The value of 'n' is:

A

10

B

11

C

20

D

9

Question 114: Palette 114/178

Allen MCQ

A battery consists of a variable number 'n' of identical cells (having internal resistance 'r' each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n?

A

B

C

D

Question 115: Palette 115/178

Allen MCQ

Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is

A

40 Ω

B

25 Ω

C

250 Ω

D

500 Ω

Question 116: Palette 116/178

Allen MCQ

Six similar bulbs are connected as shown in the figure with a DC source of emf E, and zero internal resistance. The ratio of power consumption by the bulbs when (i) all are glowing and (ii) in the situation when two from section A and one from section B are glowing, will be :

A

$4:9$

B

$9:4$

C

$1:2$

D

$2:1$

Question 117: Palette 117/178

Allen MCQ

Which of the following acts as a circuit protection device?

A

conductor

B

inductor

C

switch

D

fuse

Question 118: Palette 118/178

Allen MCQ

In the circuits shown below, the readings of the voltmeters and the ammeters will be : Circuit 1 Circuit 2

A

$V_{2} > V_{1}$ and $i_{1} = i_{2}$

B

$V_{1} = V_{2}$ and $i_{1} > i_{2}$

C

$V_{1} = V_{2}$ and $i_{1} = i_{2}$

D

$V_{2} > V_{1}$ and $i_{1} > i_{2}$

Question 119: Palette 119/178

Allen MCQ

The reading of an ideal voltmeter in the circuit shown is :

A

0.6 V

B

0 V

C

0.5 V

D

0.4 V

Question 120: Palette 120/178

Allen MCQ

The metre bridge shown is in balanced position with $\frac{P}{Q}=\frac{\ell_{1}}{\ell_{2}}$ . If we now interchange the positions of galvanometer and cell, will the bridge work? If yes, what will be balance condition?

A

yes, $\frac{\mathrm{P}}{\mathrm{Q}} = \frac{\ell_2 - \ell_1}{\ell_2 + \ell_1}$

B

no, no null point

C

yes, $\frac{\mathrm{P}}{\mathrm{Q}} = \frac{\ell_2}{\ell_1}$

D

yes, $\frac{\mathrm{P}}{\mathrm{Q}} = \frac{\ell_1}{\ell_2}$

Question 121: Palette 121/178

Allen MCQ

A charged particle having drift velocity of $7.5 \times 10^{-4} \, ms^{-1}$ is an electric field of $3 \times 10^{-10} \, Vm^{-1}$ , has a mobility in $m^{2} \, V^{-1} \, s^{-1}$ of:

A

$2.25 \times 10^{-15}$

B

$2.25 \times 10^{15}$

C

$2.5 \times 10^{6}$

D

$2.5 \times 10^{-6}$

Question 122: Palette 122/178

Allen MCQ

Which of the following graph represents the variation of resistivity ( $\rho$ ) with temperature (T) for copper?

A

B

C

D

Question 123: Palette 123/178

Allen MCQ

A resistance wire connected in the left gap of a metre bridge balances a $10 \Omega$ resistance in the right gap at a point which divides the bridge wire in the ratio 3:2. If the length of the resistance wire is 1.5 m, then the length of $1 \Omega$ of the resistance wire is :

A

$1. 5 \times 1 0 ^ {- 2}$

B

$1.0 \times 10^{-2} \mathrm{~m}$

C

$1. 0 \times 1 0 ^ {- 1}$

D

$1.5 \times 10^{-1} \mathrm{~m}$

Question 124: Palette 124/178

Allen MCQ

For the circuit shown in the figure, the current I will be

A

$0.75\mathrm{A}$

B

$1\mathrm{A}$

C

$1.5\mathrm{A}$

D

$0.5\mathrm{A}$

Question 125: Palette 125/178

Allen MCQ

For the circuit given below, the Kirchhoff's loop rule for the loop BCDEB is given by the equation

A

$-\mathrm{i}_2\mathrm{R}_2 + \mathrm{E}_2 - \mathrm{E}_3 + \mathrm{i}_3\mathrm{R}_1 = 0$

B

$\mathrm{i}_2\mathrm{R}_2 + \mathrm{E}_2 - \mathrm{E}_3 - \mathrm{i}_3\mathrm{R}_1 = 0$

C

$\mathrm{i}_2\mathrm{R}_2 + \mathrm{E}_2 + \mathrm{E}_3 + \mathrm{i}_3\mathrm{R}_1 = 0$

D

$-\mathrm{i}_2\mathrm{R}_2 + \mathrm{E}_2 + \mathrm{E}_3 + \mathrm{i}_3\mathrm{R}_1 = 0$

Question 126: Palette 126/178

Allen MCQ

The equivalent resistance between A and B for the mesh shown in the figure is

A

$7.2\Omega$

B

$16\Omega$

C

$30\Omega$

D

$4.8\Omega$

Question 127: Palette 127/178

Allen MCQ

Two solid conductors are made up of same material, have same length and same resistance. One of them has a circular cross section of area $A_{1}$ and the other one has a square cross section of area $A_{2}$ . The ratio $A_{1}/A_{2}$ is

A

1.5

B

1

C

0.8

D

2

Question 128: Palette 128/178

Allen Match the Columns

gives certain physical terms associated with flow of current through a metallic conductor. gives some mathematical relations involving electrical quantities. Match and with appropriate relations.

Column-I	Column-II
(A) Drift Velocity (B) Electrical Resistivity (C) Relaxation Period (D) Current Density	(P) $\frac{m}{ne^{2}\rho}$ (Q) $nev_{d}$ (R) $\frac{eE}{m}\tau$ (S) $\frac{E}{J}$

A

(A)-(R), (B)-(S), (C)-(P), (D)-(Q)

B

(A)-(R), (B)-(S), (C)-(Q), (D)-(P)

C

(A)-(R), (B)-(P), (C)-(S), (D)-(Q)

D

(A)-(R), (B)-(Q), (C)-(S), (D)-(P)

Question 129: Palette 129/178

Allen MCQ

The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section and same material is 0.25 Ω. What will be the effective resistance if they are connected in series?

A

0.25 Ω

B

0.5 Ω

C

1 Ω

D

4Ω

Question 130: Palette 130/178

Allen MCQ

Three resistors having resistances $r_{1}$ , $r_{2}$ and $r_{3}$ are connected as shown in the given circuit. The ratio $\frac{i_{3}}{i_{1}}$ of currents in terms of resistances used in the circuit is :

A

$\frac{\mathrm{r}_1}{\mathrm{r}_2 + \mathrm{r}_3}$

B

$\frac{\mathrm{r}_2}{\mathrm{r}_2 + \mathrm{r}_3}$

C

$\frac{\mathrm{r}_1}{\mathrm{r}_1 + \mathrm{r}_2}$

D

$\frac{\mathrm{r}_2}{\mathrm{r}_1 + \mathrm{r}_3}$

Question 131: Palette 131/178

Allen MCQ

Two hollow conducting spheres of radii $R_{1}$ and $R_{2}$ ( $R_{1} >> R_{2}$ ) have equal charges. The potential would be :

A

more on smaller sphere

B

equal on both the spheres

C

dependent on the material property of the sphere

D

more on bigger sphere

Question 132: Palette 132/178

Allen MCQ

Two resistors of resistance, 100 $\Omega $ and 200 $\Omega $ are connected in parallel in an electrical circuit. The ratio of the thermal energy developed in 100 $\Omega $ to that in 200 $\Omega $ in a given time is :

A

2 : 1

B

1 : 4

C

4 : 1

D

1 : 2

Question 133: Palette 133/178

Allen MCQ

As the temperature increase, the electrical resistance:

A

decreases for both conductors and semiconductors

B

increases for conductors but decreases for semiconductors

C

decreases for conductors but increase for semiconductors

D

increases for both conductors and semiconductors.

Question 134: Palette 134/178

Allen MCQ

A copper wire of length 10 m and radius $\left(10^{-2}/\sqrt{\pi}\right)$ m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10 (V/m) is:

A

$10^{6}$ A/m $^{2}$

B

$10^{-5}$ A/m $^{2}$

C

$10^{5}$ A/m $^{2}$

D

$10^{4}$ A/m $^{2}$

Question 135: Palette 135/178

Allen MCQ

A wheatstone bridge is used to determine the value of unknown resistance X by adjusting the variable resistance Y as shown in the figure. For the most precise measurement of X, the resistances P and Q :

A

should be approximately equal and are small

B

should be very large and unequal

C

do not play any significant role

D

should be approximately equal to 2X

Question 136: Palette 136/178

Allen MCQ

A cell of emf 4 V and internal resistance 0.5 Ω is connected to a 7.5 Ω external resistance. The terminal potential difference of the cell is :

A

3.75 V

B

4.25 V

C

4 V

D

0.375 V

Question 137: Palette 137/178

Allen MCQ

The equivalent resistance of the infinite network given below is :

A

$2\Omega$

B

$(1 + \sqrt{2})\Omega$

C

$(1 + \sqrt{3})\Omega$

D

$(1 + \sqrt{5})\Omega$

Question 138: Palette 138/178

Allen MCQ

The reciprocal of resistance is:

A

reactance

B

mobility

C

conductivity

D

conductance

Question 139: Palette 139/178

Allen MCQ

The sliding contact C is at one fourth of the length of the potentiometer wire (AB) from A as shown in the circuit diagram. If the resistance of the wire AB is $R_{0}$ , then the potential drop (V) across the resistor R is:

A

$\frac{4\mathrm{V}_0\mathrm{R}}{3\mathrm{R}_0 + 16\mathrm{R}}$

B

$\frac{4\mathrm{V}_0\mathrm{R}}{3\mathrm{R}_0 + \mathrm{R}}$

C

$\frac{2\mathrm{V}_0\mathrm{R}}{4\mathrm{R}_0 + \mathrm{R}}$

D

$\frac{2\mathrm{V}_0\mathrm{R}}{2\mathrm{R}_0 + 3\mathrm{R}}$

Question 140: Palette 140/178

Allen MCQ

The magnitude and direction of the current in the following circuit is :-

A

0.5 A from A to B through E

B

$\frac{5}{9}$ A from A to B through E

C

1.5 A from B to A through E

D

0.2 A from B to A through E

Question 141: Palette 141/178

Allen MCQ

If the galvanometer G does not show any deflection in the circuit shown, the value of R is given by :

A

$50\Omega$

B

$100\Omega$

C

$400\Omega$

D

$200\Omega$

Question 142: Palette 142/178

Allen MCQ

The resistance of platinum wire at $0^{\circ}C$ is $2\Omega$ and $6.8\Omega$ at $80^{\circ}C$ . The temperature coefficient of resistance of the wire is:

A

$3 \times 10^{-3} \, ^{\circ}C^{-1}$

B

$3 \times 10^{-2} \, ^{\circ}C^{-1}$

C

$3 \times 10^{-1} \, ^{\circ}C^{-1}$

D

$3 \times 10^{-4} \, ^{\circ}C^{-1}$

Question 143: Palette 143/178

Allen MCQ

10 resistors, each of resistance R are connected in series to a battery of emf E and negligible internal resistance. Then those are connected in parallel to the same battery, the current is increased n times. The value of n is: -

A

100

B

1

C

1000

D

10
P

Question 144: Palette 144/178

Allen MCQ

A certain wire A has resistance 81 Ω. The resistance of another wire B of same material and equal length but of diameter thrice the diameter of A will be:

A

81 Ω

B

9 Ω

C

729 Ω

D

243 Ω

Question 145: Palette 145/178

Allen MCQ

A copper wire of radius 1 mm contains $10^{22}$ free electrons per cubic metre. The drift velocity for free electrons when 10 A current flows through the wire will be (Given, charge on electron = $1.6 \times 10^{-19}$ C):

A

$\frac{6.25 \times 10^{4}}{\pi} ms^{-1}$

B

$\frac{6.25}{\pi} \times 10^{3} ms^{-1}$

C

$\frac{6.25}{\pi} ms^{-1}$

D

$\frac{6.25 \times 10^{5}}{\pi} ms^{-1}$

Question 146: Palette 146/178

Allen MCQ

The terminal voltage of the battery, whose emf is 10V and internal resistance 1Ω, when connected through an external resistance of 4Ω as shown in the figure.

A

4V

B

6V

C

8V

D

10V

Question 147: Palette 147/178

Allen MCQ

A wire of length ' $\ell'$ and resistance 100 $\Omega$ is divided into 10 equal parts. The first 5 parts are connected in series while the next 5 parts are connected in parallel. The two combinations are again connected in series. The resistance of this final combination is:

A

26 $\Omega$

B

52 $\Omega$

C

55 $\Omega$

D

60 $\Omega$

Question 148: Palette 148/178

Allen MCQ

Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is:

A

1:1

B

2:9

C

1:2

D

2:3

Question 149: Palette 149/178

Allen MCQ

A uniform wire of diameter d carries a current of 100 mA when the mean drift velocity of electrons in the wire is v. For a wire of diameter $\frac{d}{2}$ of the same material to carry a current of 200 mA, the mean drift velocity of electrons in the wire is:

A

4 v

B

8 v

C

v

D

2 v

Question 150: Palette 150/178

Allen MCQ

A uniform metal wire of length $\ell$ has $10\Omega$ resistance. Now this wire is stretched to a length $2\ell$ and then bent to form a perfect circle. The equivalent resistance across any arbitrary diameter of that circle is:

A

$10\Omega$

B

$5\Omega$

C

$40\Omega$

D

$20\Omega$

Question 151: Palette 151/178

Allen MCQ

The given circuit shows a uniform straight wire AB of 40 cm length fixed at both ends. In order to get zero reading in the galvanometer G, the free end of J is to be placed from B at :

A

$32 \mathrm{~cm}$

B

8 cm

C

16 cm

D

24 cm

Question 152: Palette 152/178

Allen MCQ

Three voltmeters all having different resistance, are joined as shown. When some potential difference is applied across A and B, their readings are $V_{1}$ , $V_{2}$ and $V_{3}$ . Then

(a) $V_{1} = V_{2}$ (b) $V_{1} \neq V_{2}$ (c) $V_{1} + V_{2} = V_{3}$ (d) $V_{1} + V_{2} > V_{3}$

A

only a is correct

B

only b is correct

C

only c is correct

D

only b & c are correct

Question 153: Palette 153/178

Allen MCQ

In the circuit shown in figure it is given that $V_{b} - V_{a} = 2$ volt. Choose the correct options.

(a) Current in the wire is 6 A
(b) Direction of current is from a to b
(c) $V_{a} - V_{c} = -12$ volt
(d) $V_{c} - V_{a} = -12$ volt

A

only a & b

B

only b & c

C

only a & c

D

all

Question 154: Palette 154/178

Allen MCQ

A battery of e.m.f E and internal resistance r is connected to a resistance R which can be adjusted to any value greater than or equal to zero. A graph is plotted between the current passing through the resistance (I) and potential difference (V) across it. Select the correct alternatives

(a) Internal resistance of the battery is 5Ω
(b) emf of the battery is 10 V
(c) maximum current which can be taken from the battery is 2A
(d) V-I graph can never be a straight lines as shown in the figure
(1) only a & b

B

a, b & c

C

only b & c

D

all

Question 155: Palette 155/178

Allen MCQ

Two heaters designed for the same voltage V have different power ratings. When connected individually across a source of voltage V, they produce H amount of heat each in times $t_{1}$ and $t_{2}$ respectively. When used together across the same source, they produce H amount of heat in time t. Then correct option is
(a) If they are in series, $t = t_{1} + t_{2}$ (b) If they are in series, $t = 2(t_{1} + t_{2})$ (c) If they are in parallel, $t = \frac{t_{1}t_{2}}{(t_{1} + t_{2})}$ (d) If they are in parallel, $t = \frac{t_{1}t_{2}}{2(t_{1} + t_{2})}$

A

only a & c

B

only a & b

C

only c & d

D

all

Question 156: Palette 156/178

Allen MCQ

In the network shown in figure, points A, B and C are at potentials of 70 V, 0 and 10 V respectively.

(a) Point D is at a potential of 40V.
(b) The currents in the sections AD, DB, DC are in the ratio 3:2:1
(c) The currents in the sections AD, DB, DC are in the ratio 1:2:3.
(d) The network draws a total power of 200 W.

A

only a is correct

B

a and c are correct

C

a, b, d are correct

D

None of these

Question 157: Palette 157/178

Allen MCQ

When some potential difference is maintained between A and B, current I enters the network at A and leaves at B see figure.

(a) The equivalent resistance between A and B is $8\Omega$
(b) C and D are at the same potential.
(c) No current flows between C and D
(d) Current 3I/5 flows from D to C.

A

a, b, d are correct

B

a, d are correct

C

a, c, d are correct

D

all are correct

Question 158: Palette 158/178

Allen MCQ

For the circuit shown in figure, match the two columns.

Column-I	Column-II
(A) Current in wire ae (B) Current in wire be (C) Current in wire ce (D) Current in wire de	(P) 1 A (Q) 2 A (R) 0.5 A (S) Zero

A

A-Q, B-S, C-Q, D-S

B

A-Q, B-Q, C-S, D-P

C

A-P, B-R, C-S, D-Q

D

A-Q, B-R, C-P, D-S

Question 159: Palette 159/178

Allen MCQ

Current i is flowing through a wire of non-uniform cross section as shown. Match the following two columns.

Column-I	Column-II
(A) Current density (B) Electric field (C) Resistance per unit length (D) Potential difference per unit length	(P) is more at 1 (Q) is more at 2 (R) is same at both sections 1 and 2 (S) data insufficient

A

A-P, B-P, C-P, D-P

B

A-Q, B-R, C-S, D-P

C

A-Q, B-Q, C-P, D-P

D

A-P, B-Q, C-R, D-S

Question 160: Palette 160/178

Allen MCQ

In the circuit shown in figure, after closing the switch S, match the following two columns.

Column-I	Column-II
(A) Current through $R_1$ (B) Current through $R_2$ (C) Potential difference across $R_1 $ (D) Potential difference across $R_2$	(P) will increase (Q) will decrease (R) will remain same (S) data insufficient

A

A-P, B-Q, C-R, D-S

B

A-P, B-R, C-S, D-Q

C

A-P, B-R, C-S, D-P

D

A-Q, B-P, C-Q, D-P

Question 161: Palette 161/178

Allen MCQ

Match the following two columns.

Column-I	Column-II
(A) Electrical resistance (B) Electrical potential (C) Specific resistance (D) Specific conductance	(P) $[ML^3T^{-3}A^{-2}]$ (Q) $[ML^2T^{-3}A^{-2}]$ (R) $[ML^2T^{-3}A^{-1}]$ (S) None of these

A

A-Q, B-S, C-R, D-P

B

A-Q, B-R, C-P, D-S

C

A-P, B-Q, C-S, D-R

D

A-P, B-R, C-Q, D-S

Question 162: Palette 162/178

Allen MCQ

In the circuit shown in the figure, match the following two columns:

Column-I	Column-II
(A) Potential difference across battery A (B) Potential difference across battery B (C) Net power consumed by R (D) Potential difference across R	(P) Zero (Q) 1 (R) 2 (S) 3

A

A-P, B-Q, C-R, D-S

B

A-S, B-Q, C-R, D-P

C

A-S, B-R, C-Q, D-Q

D

A-Q, B-R, C-S, D-S

Question 163: Palette 163/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Drift velocity of electron in a metallic wire will decrease if temperature of wire is increased
Reason (R) : On increasing temperature conductivity of metallic wire decreases.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 164: Palette 164/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Resistance of ammeter is less than resistance of milliammeter, (If made from same galvanometer)
Reason (R) : Value of shunt resistance in case of ammeter is more than a milliammeter.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 165: Palette 165/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Electric field is present inside the current carrying wire.
Reason (R) : The principle of conservation of charge is followed, when charges are in motion.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 166: Palette 166/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In balanced Wheatstone bridge, the current through cell depends on resistance of galvanometer.
Reason (R) : At balanced condition current through galvanometer is zero.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 167: Palette 167/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In series combination of electrical bulb, lower power rating bulb emits more light than that of higher power rating bulb.
Reason (R): The lower power rating bulb in series gets more current than the higher power rating bulb.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 168: Palette 168/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): When an external resistor of resistance R (connected across a cell of internal resistance r) is varied, power consumed by resistance R is maximum when R = r.
Reason (R): Power consumed by a resistor of constant resistance R is maximum when current through it is maximum.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 169: Palette 169/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Ohm's law holds only for small currents in metallic wire not for high currents.
Reason (R): For metallic wire resistance increases with increase in temperature.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 170: Palette 170/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In a Meter Bridge experiment, null point for an unknown resistance is measured. Now, the unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same point as before by decreasing the value of the standard resistance.
Reason (R): Resistance of a metal increases with increase in temperature.
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 171: Palette 171/178

Allen MCQ

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Kirchoff's loop law represents conservation of energy
Reason (R) : If the sum of "Potential Differences" around a closed loop is zero, unlimited energy could be gained by repeatedly carrying a charge around a loop
In the light of the above statements,
choose the most appropriate answer from the options given below:

A

Both (A) and (R) are true and (R) is the correct explanation of (A).

B

Both (A) and (R) are true and (R) is NOT the correct explanation of (A).

C

(A) is true but (R) is false.

D

(A) is false but (R) is true.

Question 172: Palette 172/178

Allen MCQ

If the current in resistance of uniform cross section is doubled then, (assume temperature to be approximately constant).
(A) the current density is doubled
(B) the conduction electron density is doubled
(C) the mean time between collision is constant
(D) the electron drift speed is doubled

A

A, C, D

B

B, C, D

C

A, B, C

D

A, B, C, D

Question 173: Palette 173/178

Allen Match the Columns

A resistor of varying cross-section is attached with a battery as shown. Variation of area from both ends are similar and areas are same at ends and maximum at centre. Match the approximate graphical representation of various physical properties in columns, where x axis represents position from end A of resistor and y-axis various physical properties. Match Column-I with Column-II

Column-I	Column-II
(A) i (current) (B) j (current density) (C) E (electric field) (D) $V_{d}$ (potential)	(P) (Q) (R) (S) (T)

A

A → S, B → P, C → P, D → R

B

A → Q, B → P, C → P, D → R

C

A → T, B → Q, C → P, D → S

D

A → Q, B → P, C → P, D → T

Question 174: Palette 174/178

Allen MCQ

In the given circuit the current flowing through the resistance 20 ohms is 0.3 ampere while the ammeter reads 0.9 ampere. What is the value of $R_{1}$ (in ohms).

A

20Ω

B

15Ω

C

30Ω

D

60Ω

Question 175: Palette 175/178

Allen MCQ

Statement 1: Voltage across a battery is always less than its emf. and Statement 2 : There is always some loss of energy due to internal resistance of the battery. .

A

If both statements are TRUE and STATEMENT 2 is the correct explanation of STATEMENT 1.

B

If both statements are TRUE but STATEMENT 2 is not the correct explanation of STATEMENT 1.

C

If STATEMENT 1 is TRUE and STATEMENT 2 is FALSE.

D

If STATEMENT 1 is FALSE but STATEMENT 2 is TRUE.

Question 176: Palette 176/178

Allen MCQ

Voltmeter of resistance $10\Omega$ and ammeter of resistance $10\Omega$ are attached in the following circuit with switches $S_{1}$ and $S_{2}$

Column-I	Column-II
(A) $S_{1}$ open, $S_{2}$ closed (B) $S_{1}$ closed, $S_{2}$ open (C) $S_{1}$ open, $S_{2}$ open (D) $S_{1}$ closed, $S_{2}$ closed	(P) 0, 7.5 A (Q) 50 V, 10A (R) 0, 0 (S) 150 V, 0

A

A → S, B → R, C → P, D → Q

B

$A \to Q, B \to R, C \to P, D \to S$

C

$A \to Q, B \to P, C \to R, D \to S$

D

$\mathrm{A}\rightarrow \mathrm{S},\mathrm{B}\rightarrow \mathrm{P},\mathrm{C}\rightarrow \mathrm{R},\mathrm{D}\rightarrow \mathrm{Q}$

Question 177: Palette 177/178

Allen Match the Columns

The below table is: Match Column-I(Situration) with Column-II(Values in MKS units)

Column-I

Column-II

(A) Magnitude of electric field at (1,1,1) if potential is given by $V = -\frac{1}{x} - \frac{1}{y} - \frac{1}{z}$, is (B) The charge flowing through a resistance 6Ω varies with t as Q = 4t - 2t2. The total heat produced in resistance till the current reach to zero. (C) A milliammeter of range 10mA has a coil of resistance 0.99 Ω. To use it as an ammeter of range 1A, the required shunt must have a resistance of (D) Two unlike point charges of same magnitude 10 mC are placed on x-axis at a separation of 8 cm. If both charges placed symmetrically about origin in external electric field $\vec{E}=500Vm^{-1} \hat{i}$.Then potential energy of the system may be [Assume potential energy to be zero when dipole is perpendicular to electric field]<

(P) 0.4 (Q) $\sqrt{3}$ (R) 0.01 (S) 32

A

A → Q, B → S, C → P, D → R

B

A → S, B → Q, C → R, D → P

C

A → Q, B → S, C → R, D → P

D

A → S, B → Q, C → P, D → R

Question 178: Palette 178/178

Allen MCQ

Statement-1: In real battery total chemical energy lost in the battery can not be obtained at load resistance. Statement-2 : Two heaters with different resistance are connected in parallel. Higher resistance heater will glow more.

A

If both statements are TRUE and STATEMENT 2 is the correct explanation of STATEMENT 1.

B

If both statements are TRUE but STATEMENT 2 is not the correct explanation of STATEMENT 1.

C

If STATEMENT 1 is TRUE and STATEMENT 2 is FALSE.

D

If STATEMENT 1 is FALSE but STATEMENT 2 is TRUE.