Question

Define mobility of a charge carrier. What is its relation with relaxation time?

Answer 1

Mobility:

1. Mobility is explained as the velocity of the electron per unit of the electric field.
2. It helps the electrons to can travel in conductor.
3. Therefore, the mobility of the electrons is directly proportional to the relaxation time of the electron.

On the basis of the question:

1. The mobility of a charge carrier is defined as the drift velocity of the charge carrier per unit of an electric field.
2. Thus, mobility $\mu =\frac{V_d}{E}$
3. If $q$ be the charge of the carrier and $\tau$ is the relaxation time.
4. then mobility ​$\mu =\frac{q\tau }{m}$

where m is the mass of the charge carrier.