Question

one thousand small identical charged mercury drops each having energy of 0.2 erg form a big drop. what is the energy of big drop.​

Answer 1

Let R be the radius of bigger drop after combining n drops and r be the radius of small drops.

3

4

πR

3

=n

3

4

πr 3 ⇒R=n 31 rnow, Q big =nQ small ,V big =k RQ big=k n 31rnQ small =n 32 k rQ small=n 32V smallQ big =C big V bigor C big = V big

Q big = n 32 V smallnQ small=n 31 C smallhere, n=64,C

big=(64) 31 C small =4C small