A charge Q is distributed over two concentric hollow spheres of radii r and `R (gt r)` such that the surface charge densities are equal. Find the potential at the common centre.

Options

A. `(Q(r+R))/(4pi in_(0) R^(2))`
B. `(Q(r+R))/(4(r^(2) + R^(2)) pi in_(0))`
C. `(Q)/(4sqrt(r^(2) + R^(2)))`
D. `(Q(r+ R))/(4pi in_(0))`

Answer

B