Temperature dependence of resistivity \(\rho(T)\) of semiconductors, insulators, and metals is significantly based on the following factors:

(a) number of charge carriers can change with temperature \(T\).
(b) the time interval between two successive collisions can depend on \(T\).
(c) length of material can be a function of \(T\).
(d) mass of carriers is a function of \(T\).

Which of the above statements is correct?

1. (a, b) 2. (c, d)
3. (b, c) 4. (b, d)
(1) Hint: The resistivity of a material depends on the no. of free electrons and the no. of collisions between them.
Step 1: Find the resistivity of the conductor.

The resistivity of a metallic conductor is given by,

ρ=mne2τ

where n is the number of charge carriers per unit volume which can change with temperature T and it is the time interval between two successive collisions which decreases with the increase of temperature in metals.

Also, the no. of charge carriers in semiconductors increases with temperature.