Question

1000 small water drops, each of radius r and charge q, coalesce to form a single big drop. The potential of big drop, how much times the small drop is:
(a) 1000
(b) 100
(c) 10
(d) 1

Answer 1

(b) 100
V_large = n^2/3V_small
V_large = (10³)^2/3V_small
[∵ n = 1000, n = 10³]
∴ V_large = 10²V_small = 100V_small