(a) (i) R = ρl/A
Here, A = 1 x 1cm2= 10-4m2; l = 0.5m
∴ R = 3.5 x 10-5 x 0.5/10-4 = 0.175Ω
(ii) Here, l = 1cm; A = 1 x 50cm2 = 5 x 10-3m2
R = 3.5 x 10-5 x 10-2/5 x 10-3 = 7 x 10-5Ω
(b) (i) Q = It = 5 x (4 x 60) = 1200C
(ii) n = Q/e = 1200/(1.6 x 10-19) = 75 x 1020