Two thin conducting concentric shells of radii $\mathrm{R}$ and $2 \mathrm{R}$ are shown in the figure. The…
Two thin conducting concentric shells of radii $\mathrm{R}$ and $2 \mathrm{R}$ are shown in the figure. The outer shell carries a charge $+Q$ and the inner shell is neutral. Then the correct statement/s is
(a) When the switch is closed, the potential on the inner shell becomes zero
(b) With the switch closed, the charge on the inner sphere is $\frac{Q}{2}$
(a) and (b) are correct
(a) is correct, (b) is wrong
(a) is wrong, (b) is correct
(a) and (b) are wrong
Solution
Let charge on inner shell after switch is closed be $q$ then, $\mathrm{V}_{\text {inner }}=\mathrm{V}_{\text {outer }}$
$
\frac{K q}{R}+\frac{K(Q-q)}{2 R}=\frac{K q}{2 R}+\frac{K(Q-q)}{2 R}
$
$
\therefore \mathrm{q}=0
$
