set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

For dynamo which one of the following statements is correct?

a) It converts the kinetic energy into heat energy

b) It converts the mechanical energy into electrical energy

c) It converts the electrical energy into light energy

d) It converts the electrical energy into mechanical energy

Question : 2

Assertion (A):
The temperature of a metal wire rises when an electric current is passed through it.
Reason (R):
Collision of metal atoms with each other releases heat energy.
Code

a) (A) is true, but (R) is false

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

c) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

d) (A) is false, but (R) is true

Question : 3

In an intrinsic semiconductor

a) both holes and electrons carry current

b) both holes and electrons carry current with electrons being majority carriers

c) only electrons are responsible for flow of current

d) only holes are responsible for flow of current

Question : 4

The permanent magnet is made from which one of the following substances?

a) Ferromagnetic

b) Diamagnetic

c) Paramagnetic

d) Electromagnetic

Question : 5

Function of rectifier is

a) To convert D.C. into A.C.

b) To convert A.C. into D.C.

c) Both (a) and (b)

d) None of these

Question : 6

If potential difference and current flowing through a wire is increased twice each, then electric power

a) Will increase two times

b) Will remain unaffected

c) Will increase four times

d) Will decrease half