The potential of a large liquid drop when eight liquid drops are combined is 20 V. Then the potential of each single drop was

Options

(a) 10 V
(b) 7.5 V
(c) 5 V
(d) 2.5 V

Correct Answer:

5 V

Explanation:

Volume of 8 drops = Volume of bigger drop
or, [(4/3) πr³] × 8 = (4/3) πR³ or 2r = R ——(i)
Charge is conserved. 8q = Q
.·. V’ = q / capacity = q / 4πε₀r
V = Q / capacity = Q / 4πε₀R
Then , V’ / V = (q / Q) × (R / r) or, V’ / 20 = (q / 8q) × (2r / r) = 1 / 4
or, V’ = 5 volt.