(a) Differentiate between the random velocity and the drift velocity of electrons in an electrical conductor. Give their order of magnitudes.
(b) A conductor of uniform cross-sectional area is connected across a dc source of variable voltage. Draw a graph showing variation of drift velocity of electrons (vd ) as a function of current density (J) in it.
a) Random velocity: The velocity acquired by the free electrons in the absence of
electric field. Average random velocity=0
Drift velocity: The average velocity acquired by the free electrons in presence of the electric field. Average drift velocity is non zero
Drift speed is nearly times smaller than random velocity
b)