$64$ drops of mercury,each charged to a potential of $10\,V$,are combined to form one bigger drop. The potential of this bigger drop will be.......$V$ (Assume all the drops to be spherical).

If on two concentric hollow spheres of radii $R$ and $r$ $(R < r)$,a total charge $Q$ is distributed such that their surface charge densities are equal,then the potential at their common centre is:

The electric potential energy of a $2 \mu C$ charge is $3 \times 10^{-5} \text{ J}$ at a point in a uniform electric field. The electric potential at the point is . . . . . . $V$.

Choose the $CORRECT$ option.

Two metal spheres of radii $R_1$ and $R_2$ are charged to the same potential. The ratio of charges on the spheres is

$A$ $200 \text{ J}$ of work is done in moving a charge of $5 \text{ C}$ from a point $A$ where the potential is $-20 \text{ V}$ to another point $B$ where the potential is $V \text{ V}$. The value of $V$ at point $B$ is: (in $text{ V}$)