There are two equipotential surfaces as shown in the figure. The distance between them is $r$. If a charge of $-q \text{ C}$ is moved from surface $A$ to surface $B$,the resultant work done will be:

Prove that a closed equipotential surface with no charge within itself must enclose an equipotential volume.

In the figure,the charge $Q$ is at the centre of the circle. Work done is maximum when another charge is taken from point $P$ to:

Equipotential surfaces are given as shown. The electric field intensity is ........

At which point is the electric field maximum?

This question has Statement-$1$ and Statement-$2$. Of the four choices given after the Statements,choose the one that best describes the two Statements.
Statement-$1$: No work is required to be done to move a test charge between any two points on an equipotential surface.
Statement-$2$: Electric lines of force at the equipotential surfaces are mutually perpendicular to each other.