Question

What is the drift velocity of an electron in a copper conductor having area 10 × 10⁻⁶m², carrying a current of 2 A. Assume that there are 10 × 10²⁸ electrons / m³.

Answer 1

Given conditions ⇒

Area(A) = 10 × 10⁻⁶ m²
 = 10⁻⁵ m²

Current(I) = 2 A.
Number of the Electrons per m³ (n) = 10 × 10²⁸
 = 10²⁹

Now, Using the Formula,
 v = I/Anq
where, q is the charge on 1 electron = 1.6 × 10⁻¹⁹ C and v is the drift velocity. 

∴ v = 2/(10⁻⁵ × 10²⁹ × 1.6 × 10⁻¹⁹)
⇒ v = 1.6/(20 × 10⁵)
⇒ v = 0.08 × 10⁻⁵ m²/Vs.


Hope it helps.

Answer 2

Solution:
Current=I=2A
Area=A=10 × 10⁻⁶m²=10^-5m²

Number of electrons= n=10 × 10²⁸ electrons

charge on electron= 1.6 x10^-19 coulombs

Drift velocity = vd=?

Formula to be used:
**************************
vd= I/nqA

vd=2/10 × 10²⁸×1.6 x10^-19×10^-5 m/s

vd=0.125×10^-4 m/s

Therefore electron drift velocity =0.125×10^-4 m/s