Drift Velocity
The average velocity of all electron taken together is called drift velocity.
On applying external field the charges will accumulate on each side of solenoid conductor due to which and induce electric field is produced in the conductor which is equal in magnitude of external electric field but opposite in direction.
If some how the temperature of isolated conductor increase the free electron get thermal energy and will move in the electron have individual thermal velocity but be assume thermal velocity average inside the conductor.
Terms related to Drift velocity
(i) Relaxation time
The time taken by electron in two successive collision is called relaxation time. It is denoted bye tauu average.
(ii) mean free path
The distance covered by electron in two successive collagen is called Mainpuri it is denoted by lamda.