Question

The conductivity of a semiconductor increases with increase in temperature, because
(a) number density of free current carriers increases.
(b) relaxation time increases.
(c) both number density of carriers and relaxation time increase.
(d) number density of carriers increases, relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density. [NCERT Exemplar]

Answer 1

Explanation:

Answer :

D

Solution :

With increase in temperature , number of electrons reaching conduction band increases but , mean relation time decreases . Effect of decrease in relation time is much less than that of increase in number density of charge carriers.