A charge 'q' is distributed over two concentric hollow conducting sphere of radii r and R(>r) such that their surface charge densities are equal. The potential at their common centre is

Options

A. zero
B. `(q)/(4 pi in_0 ) ( (r+R ))/((r^2 +R^2)^2)`
C. `(q)/(4 pi in_0 ) [(1)/(r ) +(1)/(R ) ]`
D. `(q )/(4 pi in_0 ) [(r+R )/( (r^2 +R^2))]`

Answer

D