Question

What will be the time taken by electron to move with drift velocity from one end to the other end of copper conductor 3 metre long and carrying a current of 3 A ?
[The cross-sectional area of the conductor = 2 x 10⁻⁶ m² and electron density for copper n = 8.5 X 10²⁸ m⁻³]
(A) 2.72 x 10³s
(B) 2.72 x 10⁴s
(C) 2.72s
(D) 2.72 x 10⁻⁴s

Answer 1

Dear Student,

◆ Answer - (B)

t = 2.72×10^4 s

● Explaination -

Current flowing through conductor is given by -

I = n.A.e.v

v = I / n.A.e

v = 3 / (8.5×10^28 × 2×10^-6 × 1.6×10^-19)

v = 1.103×10^-4 m/s

Time taken for e- to move with this drift velocity is -

t = l / v

t = 3 / 1.103×10^-4

t = 2.72×10^4 s

Therefore, 2.72×10^4 s will be taken for electron to move from one end to another.

Hope this helps you...