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

Work done in moving a positive charge on an equipotential surface is

Assertion $(A):$ $A$ spherical equipotential surface is not possible for a point charge.
Reason $(R):$ $A$ spherical equipotential surface is possible inside a spherical capacitor.

Two point charges of magnitude $+q$ and $-q$ are placed at $\left( -\frac{d}{2}, 0, 0 \right)$ and $\left( \frac{d}{2}, 0, 0 \right)$,respectively. Find the equation of the equipotential surface where the potential is zero.

For an electric field that increases in magnitude along the $x$-direction,what is the nature of the equipotential surfaces?

$A$ point charge $+q$ is placed at the origin. The work done in moving another point charge $-Q$ along the straight line path $AB$ from point $A$ with coordinates $(0, a)$ to point $B$ with coordinates $(a, 0)$ is .......