Question

A larger drop is made from the two small drops each having 100V then voltage on the bigger drop is:

• A. 100 volt
• B. 1000 volt
• C. 156 volt
• D. $100\times 2^{\frac{2}{3}}$volt

Answer 1

The correct option is D $100\times 2^{\frac{2}{3}}$volt

let the radius of each drop be r and the resultant larger drop be R, then
$2\times \frac{4}{3}\pi r^3=\frac{4}{3}\pi R^3\Rightarrow R=2^{\frac{1}{3}}r100=\frac{kq}{r}totalchargeonthebiggerdrop=2qvoltageonthebiggerdropis\frac{k\times 2q}{R}=\frac{2kq}{2^{\frac{1}{3}}r}=2^{\frac{2}{3}}\times 100V$