set 6 MCQ Questions & Answers Detailed Explanation

Question : 1

In an A.C. circuit with voltage V and current I the power dissipated is

a) $1/2$VI

b) V I

c) $1/√2$VI

d) dependent on the phase between V and I

Question : 2

An AC generator of 220 V having internal resistance r = 10Ω and external resistance R = 100Ω. What is the power developed in the external circuit?

a) 400 W

b) 441 W

c) 484 W

d) 369 W

Question : 3

Consider the following statements :

1. Magnetic field produced by current in a straight wire has no poles.
2. The magnetic lines of force produced by a straight current carrying conductor are straight in nature.
3. To produce a strong magnetic field at its centre, we prefer a current carrying wire loop of larger radius.

a) 1 only

b) 1 and 3

c) 2 only

d) 1, 2 and 3

Question : 4

Which is the gas inside an electric bulb?

a) Carbon dioxide

b) Argon

c) Nitrogen

d) Both (A) and (B)

Question : 5

The charge given to any conductor resides on its outer surface, because

a) the free charge tends to be in its minimum kinetic energy state

b) the free charge tends to be in its maximum potential energy state.

c) the free charge tends to be in its minimum potential energy state

d) the free charge tends to be in its maximum kinetic energy state

Question : 6

Two pieces of conductor of same material and of equal length are connected in series with a cell. One of the two pieces has cross-sectional area double that of the other. Which one of the following statements is correct in this regard ?

a) Same amount of electric current would pass through both the pieces producing more heat in the thicker one.

b) The thicker one will allow stronger current to pass through it.

c) The thinner one would allow stronger current to pass through it.

d) Same amount of electric current would pass through both the pieces producing more heat in the thinner one.