An electric charge ${10^{ - 3}}\,\mu \,C$ is placed at the origin $(0, 0)$ of $X -Y$ co-ordinate system. Two points $A$ and $B$ are situated at $\left( {\sqrt {2\,} \,,\,\,\sqrt 2 } \right)$  and $(2, 0)$ respectively. The potential difference between the points $A$ and $B$ will be......$volt$

The charge given to a hollow sphere of radius $10\, cm$ is $3.2×10^{-19}\, coulomb$. At a distance of $4\, cm$ from its centre, the electric potential will be

If the potential of the inner shell is $10\,V$ and that of the outer shell is $5\,V$, then potential at the centre will be....$V$

Three charged concentric nonconducting shells are given as shown in figure. Find the potential at point $A$

$512$ identical drops of mercury are charged to a potential of $2\, V$ each. The drops are joined to form a single drop. The potential of this drop is ......... $V.$

$1000$ small water drops each of radius $r$ and charge $q$ coalesce together to form one spherical drop. The potential of the big drop is larger than that of the smaller drop by a factor of