The variation of electrostatic potential $V$ with radial distance $r$ from the centre of a positively charged metallic thin shell of radius $R$ is given by the graph:

$A$ regular hexagon of side $5 \, cm$ has a charge $10 \, \mu C$ at each of its vertices. The potential at the centre of the hexagon is

An electric charge $10^{-6} \mu C$ is placed at the origin $(0,0) \text{ m}$ of an $X-Y$ coordinate system. Two points $P$ and $Q$ are situated at $(\sqrt{3}, \sqrt{3}) \text{ m}$ and $(\sqrt{6}, 0) \text{ m}$ respectively. The potential difference between the points $P$ and $Q$ will be:

Two charged spheres of radii $R_1$ and $R_2$ have equal surface charge density. The ratio of their potential is

When a positive $q$ charge is taken from a lower potential point to a higher potential point,its potential energy will

Two points $P$ and $Q$ are maintained at the potentials of $10\, V$ and $-4\, V$,respectively. The work done in moving $100$ electrons from $P$ to $Q$ is: