n = 8 x 1028 m-3 ; l = lm
A= 8 x 1028 m-2 ; e = 1.6 x 10-9C
Total charge contained in the wire
q = volume of wire x ne = Alne = 8 x 10-6 x 1 x 8 x1028 x 1.6 x 10-19 C
= 102.4 x 103 C
If vd is the drift speed of electrons, then
F = qvd B sin 90° = qvd B
vd = 1.56 x 10 ms-1