Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0 × 10–7 m2 carrying a current of 1.5 A. Assume the density of conduction electrons to be 9 × 1028 m–3.
Flow of current in the conductor due to drift velocity of the free electrons is given by
I = neAvd
vd = l/neA
= (15/9 x 1028 x 1.6 x 10-19 x 1.0 x10-7)
vd = 1.048 x 10-3 m/ ≈ 1mm/
