question

(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)