What is relaxation time `(tau)` ?

What is reaction time ?

Derive equa1ion of mobility in terms of relaxation time (tau) . Wrile its unit.

Which graph correctly represents the variation between relaxation time (tau) of gas molecules with absolute temperature (T) of the gas?

The relaxation time tau Is nearly independent of applied E field whereas it changes significantly with temperature T. First fact is (in part) responsible for Ohnl's law whereas the second fact leads to variation of p with temperature. Elaborate why ?

Define drift velocity of free electron . If relaxation time is r then write a vector relation b etween drift velocity and electric field.

On what does the reaction time depend ?

What is the ratio between the distance travelled by the oscillator in one time period and amlitude?