$A$ spherical conductor of radius $2\,m$ is charged to a potential of $120\,V$. It is now placed inside another hollow spherical conductor of radius $6\,m$. Calculate the potential to which the bigger sphere would be raised.

$A$ capacitor of capacitance $C$ is connected to a battery of $V$ volts. Now,the distance between the plates of the capacitor is halved while keeping the charge constant,and it is again charged to $V$ volts. What is the energy supplied by the battery?

In the adjoining figure,four capacitors are shown with their respective capacities and the $P.D.$ applied. The charge and the $P.D.$ across the $4\,\mu F$ capacitor will be

$27$ identical drops of mercury are charged simultaneously with the same potential of $10 \ V$. Assuming the drops to be spherical,if all the charged drops are made to combine to form one large drop,then its potential will be . . . . . . volt.

In the figure shown below,the charge on the left plate of the $10\, \mu F$ capacitor is $-30\,\mu C.$ The charge on the right plate of the $6\,\mu F$ capacitor is.....$\mu C$.

In the electrical circuit shown below,the amount of charge stored in the capacitor is . . . . . . $\mu C$.