- Home
- Standard 12
- Physics
2. Electric Potential and Capacitance
hard
Two thin conducting shells of radii $R$ and $3R$ are shown in the figure. The outer shell carries a charge $+ Q$ and the inner shell is neutral. The inner shell is earthed with the help of a switch $S$.

A
With the switch $S$ open, the potential of the inner sphere is equal to that of the outer.
B
When the switch $S $ is closed, the potential of the inner sphere becomes zero.
C
With the switch $S$ closed, the charge attained by the inner sphere is $- q/3$.
D
all of the above
Solution

Let $q$ be the charge attained by the inner shell.
As the inner shell is earthed so potential at any point on the surface of the shell is zero
i.e. $V=0=V_{\text {in}}+V_{\text {out}}=\frac{k q}{R}+\frac{k Q}{3 R}$
$\therefore q=-\frac{Q}{3}$
Standard 12
Physics
Similar Questions
hard