Question

Relation between drift speed and area of cross section

Answer 1

Explanation:

Let us derive an relation between drift velocity and an area of cross section :

Let take a conductor and placed in an strong electric field .

And we consider at a point in a conductor to derive relation as shown in figure.

Let the area of cross section be ' A '

(n ) No. of electron that passing cross section B' in time ( dt ) = all electron contained in shaded region.

n = no. of free electron per unit volume .

dq = no. of electron × charge on electron.

dq = n × Vd . dt × A × e-

we know that

$i \: = \frac{dq}{dt}$

where: i = current , dq = small charge , dt = small time

putting the value of dq in current .

i = Vd.dt × A × e- × n / dt

i = Vd e n A ( or )

Vd = i / e n A

Some related information in Attachment

Thank you