$A$ potential at a point $A$ is $-3 \ V$ and that at another point $B$ is $5 \ V$. What is the work done in carrying a charge of $5 \ mC$ from $B$ to $A$?

$A$ hemispherical bowl of radius $R$ is uniformly charged with surface charge density $\sigma$. Find the electric potential at point $A$,which lies on the base at a distance $R/2$ from the center $O$ of the base.

The linear charge density on a dielectric ring of radius $R$ varies with $\theta$ as $\lambda = \lambda_0 \cos(\theta/2)$,where $\lambda_0$ is a constant. Find the potential at the centre $O$ of the ring.

Four charges are arranged at the corners of a square $ABCD$ of side $d$,as shown in Figure.
$(a)$ Find the work required to put together this arrangement.
$(b)$ $A$ charge $q_{0}$ is brought to the centre $E$ of the square,the four charges being held fixed at its corners. How much extra work is needed to do this?

An electric charge $10^{-8} \ C$ is placed at the point $(4 \ m, 7 \ m, 2 \ m)$. At the point $(1 \ m, 3 \ m, 2 \ m)$,the electric

Four point charges each $+q$ are placed on the circumference of a circle of diameter $2d$ in such a way that they form a square. The potential at the centre is proportional to