$A$ charge of $20 \, C$ moves through a distance of $2 \, cm$. The work done is $2 \, J$. The potential difference between the two points is ........ $V$.

Four point charges $-Q, -q, 2q$ and $2Q$ are placed,one at each corner of a square. The relation between $Q$ and $q$ for which the potential at the center of the square is zero is:

$A$ thin metallic disc is rotating with constant angular velocity about a vertical axis that is perpendicular to its plane and passes through its centre. The rotation causes the free electrons in the disc to redistribute. Assume that there is no external electric or magnetic field. Then,

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.

Two charged spheres of radii $R_1$ and $R_2$ have equal surface charge density. The ratio of their potential is

Charges of $+ \frac{10}{3} \times 10^{-9} \, C$ are placed at each of the four corners of a square of side $8 \, cm$. The potential at the intersection of the diagonals is