$A$ circle of radius $R$ is drawn with a charge $+q$ at the centre. $A$ charge $q_0$ is moved from point $B$ to $C$ along the circumference of the circle. The work done is:

Positive and negative point charges of equal magnitude are kept at $(0, 0, a/2)$ and $(0, 0, -a/2)$,respectively. The work done by the electric field when another positive point charge is moved from $(-a, 0, 0)$ to $(0, a, 0)$ is

The figure shows three points $A$,$B$,and $C$ in a region of uniform electric field $\overrightarrow{E}$. The line $AB$ is perpendicular and $BC$ is parallel to the field lines. Which of the following relations holds good? Let $V_A$,$V_B$,and $V_C$ represent the electric potential at points $A$,$B$,and $C$ respectively.

Charge $q_{2}$ is at the centre of a circular path with radius $r$. Work done in carrying charge $q_{1}$,once around this equipotential path,would be

If charge $+q$ is taken from one point to another over an equipotential surface, then

Define an equipotential surface.