Question

64 identical drops each of capacity 5F combine to form a big drop.what is the capacity of big drop?

Answer 1

we first find volume of big drop
volume of big drop=64 x volume of small drop
4/3pi.R^3=64 x 4/3pi.r^3
R=4r
because capacitance of solid spherical body directly proportion to radius
hence big drop capacitance =4 x capacitance of small

capacitance of big drop=20F

Answer 2

c=(64)^1/3 * 5

c=4*5 =20 F