Question

64 indentical drops each of capacity 5f combine to form a big drop what is the capacity of big drop

Answer 1

Radius of big drop=R

Radius of small drop=r

 

volume of big drop=64×volume of small drop

we conclude 

R=4r

Capacitance of a small drop= 4πr=5uf----------(1)

Capacitance of large drop= 4πR=Cuf...............(2)

Taking ratio we get C=20uf 

Answer 2

Radius of big drop=R

Radius of small drop=r

 

volume of big drop=64×volume of small drop

we conclude 

R=4r

Capacitance of a small drop= 4πr=5uf----------(1)

Capacitance of large drop= 4πR=Cuf...............(2)

Taking ratio we get C=20uf .............