Define the term 'drift velocity' of charge carriers in a conductor. Obtain the expression for the current density in terms of relaxation time

(a) Define the term ‘drift velocity’ of charge carriers in a conductor. Obtain the expression for the current density in terms of relaxation time.
(b) A100 V battery is connected to the electric network as shown. If the power consumed in the 2 ohm resistor is 200 W, determine the power dissipated in the 5 ohm resistor.