Question

What is the order of relaxation time?​

Answer 1

Answer:

From a practical standpoint, this is what makes metals useful as electrical conductors even at room temperature, where a relaxation time on the order of 10-14 s and a mean free path (equal to the product of the velocity and the relaxation time) on the order of 10-8 m (or about 100 atomic distances) is typical.

Answer 2

Explanation:

In pure metals at low temp, the long mean free path of conduction electrons results from their large velocity (on the order of 10⁶ m/s near the Fermi surgace) and relatively long relaxation time on the order of 10^-9 s