consider a neutral conducting sphere of radius `a` with a spherical cavity of radius `b`. A charged conducting sphere of radius `c` is placed in cavity . Centre of this sphere coincide with centre of cavity charge on the inner sphere is `q` total self energy of this arrangement is:

Options

A. `(kq^(2))/(2a)-(kq^(2))/(2c)-(kq^(2))/(2b)`
B. `(kq^(2))/(2a)+(kq^(2))/(2c)-(kq^(2))/(2b)`
C. `(kq^(2))/(a)+(kq^(2))/(c)-(kq^(2))/(b)`
D. `(kq^(2))/(2a)-(kq^(2))/(2c)-(kq^(2))/(2b)`

Answer

B

Explanation

Energy with in the cavity `=(kq^(2))/(2c)-(kq^(2))/(2b)`
Energy out side the sphere `=(kq^(2))/(2a)`
total energy `=(kq^(2))/(2a)+(kq^(2))/(2c)-(kq^(2))/(2b)`