Relaxation time is the time interval between two successive collisions of electrons in a conductor, when current flows. From this, you can find expression of relaxation time.Field is V/length and V=IR.From this you can modify the expression in terms of resistivity.
Relaxation time is the time interval between two successive collisions of electrons in a conductor, when current flows. From this, you can find expression of relaxation time.Field is V/length and V=IR.From this you can modify the expression in terms of resistivity.










