Electron volt is a unit of

When a charge of $20 C$ is taken from one point to another separated by a distance of $0.2 m$,work of $2 J$ is required to be done. What is the potential difference between the two points?

The electric potential on the surface of a hollow sphere of radius $5 \ cm$ is $10 \ V$. What is the electric potential at its center?

$A$ long,hollow conducting cylinder is kept coaxially inside another long,hollow conducting cylinder of larger radius. Both the cylinders are initially electrically neutral.

The electric potential at the centre of two concentric half rings of radii $R_1$ and $R_2$,having same linear charge density $\lambda$ is

Two unlike charges of magnitude $q$ are separated by a distance $2d$. The potential at a point midway between them is