Equipotential surfaces at a very large distance from a collection of charges whose total sum is not zero are approximately . . . . . . .

Show that the direction of the electric field at a given point is normal to the equipotential surface passing through that point.

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:

$A$ 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:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Work done by an electric field on moving a positive charge on an equipotential surface is always zero.
Reason $(R)$: Electric lines of force are always perpendicular to equipotential surfaces.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ conducting sphere of radius $r$ has a charge. Then