The conductivity of semiconductor increases with increase in temperature because

Options

A. both number density of charge carriers and relaxation time increase
B. number density of charge carriers increases
C. number density of current carriers increases,relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density
D. relaxation time increases.

Answer

C

Explanation

(c): Due to increase in temperature bonds break which liberates large number of holes and electrons (charge carriers). Relaxation time too decreases but its effect is much less.