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 $S$.

115-943

  • 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

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  • [NEET 2019]