Question

Assertion: Insulators do not allow flow of current through themselves.
Reason: They have no free charge carriers.

• A. If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion
• B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion
• C. If Assertion is true but the Reason is false
• D. If both Assertion and Reason are false

Answer 1

Answer: (A)

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