Question

The diameter of a copper wire is 2 mm, a steady current of 6.25 A is generated by $8.5\times {10}^{28}/m^2$ electron flowing through it. Calculate the drift velocity of conduction electrons.

Answer 1

$I=nAve$

$n=8.5\times {10}^{28}/m^2$

$A=\pi r^2=\pi \times {10}^{-6}{m}^2$

$e=1.6\times {10}^{-19}C$

Hence, $v=\frac{I}{nAe}=\frac{6.25}{8.5\times {10}^{28}\times \pi \times {10}^{-6}\times 1.6\times {10}^{-19}}$

$⟹v=0.146\times {10}^{-3}m/s$

$⟹v=1.46\times {10}^{-4}m/s$