Figure shows a solid hemisphere with a charge of $5\ nC$ distributed uniformly through its volume. The hemisphere lies on a plane and point $P$ is located on this plane, along a radial line from the centre of curvature at distance $15\ cm$. The electric potential at point $P$ due to the hemisphere, is .....$V$

A charge of ${10^{ - 9}}\,C$ is placed on each of the $64$ identical drops of radius $2\,cm$. They are then combined to form a bigger drop. Find its potential

Two electric charges $12\,\mu C$ and $ - 6\,\mu C$ are placed $20\, cm$ apart in air. There will be a point $P$ on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of $P$ from $ - 6\,\mu C$ charge is.......$m$

$N$ identical spherical drops charged to the same potential $V$ are combined to form a big drop. The potential of the new drop will be

A charge of total amount $Q$ is distributed over two concentric hollow spheres of radii $r$ and $R ( R > r)$ such that the surface charge densities on the two spheres are equal. The electric potential at the common centre is

Draw a graph for variation of potential $\mathrm{V}$ with distance $\mathrm{r}$ for a point charge $\mathrm{Q}$.