Electric field is always ...... to the equipotential surface at every point. (Fill in the gap)

Find the equation of the equipotential surface for an infinite cylinder of radius $r_0$,carrying a charge of linear density $\lambda$.

Equipotential surfaces associated with an electric field which is increasing in magnitude along the $x$-direction are

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:

How much work is required to move a charge $(-q)$ from point $A$ to point $C$ in the presence of a charge $+Q$ at point $B$ as shown in the figure?

$A$ 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 .......