Q.

Consider the situation shown in the figure. The capacitor A has a charge q on it whereas B is uncharged. The charge appearing on the capacitor B a long time after the switch is closed is                          [2001]

1 zero  
2 q/2  
3 q  
4 2q  

Ans.

(1)

When switch S is closed, there will be no shifting of negative charge from plate A to B as the charge −q is held by the charge +q, as unlike charges attract each other. Neither will there be any shifting of charge from B to A.

Hence, the charge on capacitor B = 0.