i = neAv or v = i/neA
∴ v = 1/(8.5 x 1028) x 1.6 x 1019 x (1 x 10-4) = 7.35 x 10-7m/s = 0.735μ
Time taken by the charge 10 travel conductor length of 10 km is
t = distance/velocity = (10 x 103)/(7.35 x 10-7) = 1.36 x 1010
Now, I year = 365 x 24 x 3600 = 31,536.000s
t = 1.36 x 1010/31,536.000 = 431 year