No current flows between two charged bodies connected together when they have the same

The given graph shows the variation (with distance $r$ from the centre) of:

When a proton is accelerated through a potential difference of $1 \, V$, its kinetic energy is .......... $eV$.

Assertion: Electrons move away from a region of higher potential to a region of lower potential.
Reason: An electron has a negative charge.

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?

There are two thin wire rings,each of radius $R$,whose axes coincide. The charges of the rings are $q$ and $-q$. The magnitude of potential difference between the centres of the rings separated by a distance $\sqrt{3} R$ is