What is the direction of the lines of force at any point on the equipotential surface?

On rotating a point charge having a charge $q$ around a charge $Q$ in a circle of radius $r$,the work done will be:

There is a uniform electric field of intensity $E$ as shown in the figure. How many labelled points have the same electric potential as the fully shaded point?

Draw an equipotential surface of two identical positive charges for small distance.

Two point charges $-Q$ and $+Q / \sqrt{3}$ are placed in the $xy$-plane at the origin $(0,0)$ and a point $(2,0)$,respectively,as shown in the figure. This results in an equipotential circle of radius $R$ and potential $V = 0$ in the $xy$-plane with its center at $(b, 0)$. All lengths are measured in meters.
$(1)$ The value of $R$ is. . . . meter.
$(2)$ The value of $b$ is. . . . . .meter.

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