in an electrical cable there is a single wire of radius 9 · 2020. 6. 18. · in an electrical...

In an electrical cable there is a single wire of radius 9

mm of copper. Its resistance is 5W. The cable is

replaced by 6 different insulated copper wires, the

radius of each wire is 3mm. Now the total resistance

of the cable will be

(A) 7.5 W (B) 45 W

(C) 90 W (D) 270 W

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MENTI QUIZ - 53

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01

Twelve wires of equal length and same cross-section

are connected in the form of a cube. If the resistance

of each of the wires is R, then the effective resistance

between the diagonal ends would be

(A) 2 R (B) 12 R

(C) (D) 8 R

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02

5

6R

A and B are two points on a uniform ring of radius

r. The resistance of the ring is R, as shown

in the figure. The equivalent resistance between

points A &B is


03

AOB

Figure shows three resistor configurations R1, R2 and R3

connected to 3V battery. If the power dissipated by the

configuration R1, R2 and R3 is P1, P2 and P3, respectively, then

(A) P1 > P2 > P3 (B) P1 > P3 > P2

(C) P2 > P1 > P3 (D) P3 > P2 > P1


04

1W

1W

1W

1W

1W

3V

R1

1W3V

R2

1W

1W1W

1W

1W 3V

R3

1W

1W

1W

1W

In the figure shown, the capacity of the condenser C

is 2 mF. The current in 2 W resistor is


05

6V 2.8W

+ –

2mF 4W

3W

2W

When the key K is pressed at time t = 0, which of the following

statements about the about the current I in the resistor AB of the

given circuit is true

(A) I = 2 mA at all t

(B) I oscillates between 1 mA and 1 mA

(C) I = 1 mA at all t

(D) At t = 0, I = 2 mA and with time it goes to 1 mA


06

B

1000W

C 1mF

A

K 2V

10

00W

If in the circuit shown below, the internal resistance

of the battery is 1.5W and VP and VQ are the

potentials at P and Q respectively, what is the

potential difference between the points P and Q

(A) Zero

(B) 4 volts (VP > VQ)

(C) 4 volts (VQ > VP)

(D) 2.5 volts (VQ > VP)


07

+ –

20V 1.5W

W

W

W

W

P

Q

Two wires of resistances R1 and R2 have temperature

coefficient of the resistances a1 and a2 respectively.

These are joined in series. The effective temperature

coefficient of resistance is


08

Two cells of equal e.m.f. and of internal resistance r1 and r2

(r1 > r2) are connected in series. On connecting this

combination to an external resistance R, it is observed that

the potential difference across the first cell becomes zero.

The value of R will be


09

In the circuit shown here, E1 = E2 = E3 = 2 V and R1

= R2 = 4 ohm. The current flowing between points A

and B through battery E2 is

(A) Zero

(B) 2 amp from A to B

(B) 2 amp from B to A

(D) None of these


10

A B

E1

E2

E3

R1

R2

In the circuit shown below E1 = 4.0, R1 = 2W, E2= 6.0

V, R2 = 4 W and R3 = 2W. The current I1 is

(A) 1.6 A

(B) 1.8 A

(C) 1.25 A

(D) 1.0 A


11

E1 = 4 V

R1 = 2 W

I2

I1

E2 = 6 V

R3 = 2 W

R2 = 4 W

A moving coil galvanometer has 150 equal divions.

Its current sensitivity is 10 divisions per milliampere

and voltage sensitivity is 2 divisons per millivolt. In

order that each division reads 1 volt, the resistance

in ohms needed to be connected in series with the

coil will be

(A) 99995 (B) 9995

(C) 103 (D) 1


12

The resistance of the series combination of two

resistances S. When they are joined in parallel the

total resistance is P. If S = nP, then the minimum

possible value of n is

(A) 4 (B) 3

(C) 2 (D) 1


13

A wire of resistance 10 W is bent to form a circle. P and Q

are points on the circumference of the dividing it into a

quadrant and are connected to a battery of 3 V and

internal resistance 1 W as shown in the figure. The currents

in the two parts of the circle are


14

3 V

P

Q 1 W

In the given circuit, with steady current, the

potential drop across the capacitor must be

(A) V

(B) V/2

(C) V/3

(D) 2V/3


15

R

2R

C

V

V

2V

What is the equivalent resistance between the points

A and B of the network


16

10W

1.8W

4W 2W

1W

1W

5W 2.2W

2W 3W 2W A

B

In the circuit element given here, if the potential at

point B, VB = 0, then the potentials of A and D are

given as


17

A B C D

1 amp 1.5 W 2.5 W 2V

Seven resistances are connected as shown in the

figure. The equivalent resistance between A and B is

(A) 3W (B) 4W

(C) 4.5 W (D) 5 Wwww.gangwarinstitue.comwww.gangwarinstitute.com Contact info : 8400-582-582, 8604-582-582

18

5W

10W

8W 6W 6W

3W

10W

A B

Length of a hollow tube is 5m, it’s outer diameter is

10 cm and thickness of it’s wall is 5mm. If resistivity

of the material of the tube is 1.7×10–8W×m

(A) 5.6 ×10–5W (B) 2 ×10–5W

(C) 4 ×10–5W (D) None of these


19

A 2 W carbon resistor is color coded with green,

black, red and brown respectively. The maximum

current which can be passed through this resistor

is

(A) 63 mA (B) 0.4 mA

(C) 100 mA (D) 20 mA


20

When the switch S, in the circuit shown, is closed

then the value of current I will be

(A) 3A

(B) 5A

(C) 4A

(D) 2A


21

A carbon resistance has a following colour code.

What is the value of the resistance


22

A potentiometer wire AB having length L and resistance 12r

is joined to a cell D of emf e and internal resistance r. A cell

C having emf e/2 and internal resistance 3r is connected.

The length AJ at which the galvanometer as shown in fig.

shows no deflection is


23

In a wheatstone bridge (see fig.) Resistances P and Q are

approximately equal. When R = 400W, the bridge is equal.

When R = 400W, the bridge is balanced, On inter-changing

P and Q, the value of R, for balance, is 405W. The value of

X is close to

(A) 403.5 ohm

(B) 404.5 ohm

(C) 401.5 ohm

(D) 402.5 ohm


24

Two equal resistance when connected in series to a

battery, consume electric power of 60W. If these

resistances are now connected in parallel

combination to the same battery, the electric power

consumed will be

(A) 60 W (B) 240 W

(C) 30 W (D) 120 W


25

The resistance of the meter bridge AB in given figure is 4W.

With a cell of emf e = 0.5V and rheostat resistance Rh = 2W

the null point is obtained at some point J. When the cell is

replaced by another one of emf e = e2 the same null point J

is found for Rh = 6W. the emf e2 is

(A) 0.6V

(B) 0.5V

(C) 0.3V

(D) 0.4V


26

A galvanometer having a resistance of 20W and 30

divisionos on both sides has figure of merit 0.005

ampere / division. The resistance that should be

connected in series such that it can be used as a

voltmeter upto 10 volt, is

(A) 80W (B) 120W

(C) 125W (D) 100W


27

In the experiment set up of metre bridge shown in the figure, the

null point is obtained at a distance of 10cm from A. If a 10W

resistor is connected in series with R1, the null point shifts by

10cm. The resistance that should be connected in parallel with

(R1+10) W such that the null point shifts back to its initial

position is

(A) 40W (B) 60W

(C) 20W (D) 30W


28

An ideal battery of 4V and resistance R are connected in

series in the primary circuit of a potentiometer of length

1 m and resistance 2W. The value of R, to give a potential

difference of 5mV across 10cm of potentiometer wire, is

(A) 490W (B) 480W

(C) 395W (D) 495W


29

For the circuit shown, with R1=1.0W, R2=2.0W, E1 = 2V

and E2 = E3 = 4V, the potential difference between the

points ‘a’ and ‘b’ is approximately (in V)

(A) 2.7

(B) 3.3

(C) 2.3

(D) 3.7


30

in an electrical cable there is a single wire of radius 9 · 2020. 6. 18. · in an electrical...

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