Question

Assertion : Insulators do not allow flow of current through themselves.

Reason: They have no free charge carriers.

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

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

The correct option is (a).

Explanation:

In an insulator, the valence band is completely filled and the conduction band is completely empty. There is no charge carriers at all in the conduction hand. Moreover as the energy gap Eg >> KBT where T is the room temperature, so no electron can jump from the valence band to the conduction band at low, temperatures and even at higher temperatures.