A charge .q. is distrubuted over two concertric hollow conducting sphere of radii r and R `(lt r)` such that their surface charge densite are equal. The potential at their common centre is

Options

A. Zero
B. `(q)/(4piepsilon_(0))((r+R))/((r^(2)+R^(2))^(2))`
C. `(q)/(4piin_(0))[(1)/(r)+(1)/(R)]`
D. `(q)/(4piin_(0))[(r+R)/((r^(2)+R^(2)))]`

Answer

D