If the electric potential of the inner shell of radius $a$ is $10\,V$ and that of the outer shell of radius $2a$ is $5\,V$,then the potential at the centre will be.....$V$

Charges $Q$ are placed at each corner of a square of side $a$. How much work is required to remove a charge $-Q$ from the center of the square and move it to infinity?

Two point charges $q_1$ and $q_2$ are separated by a distance $d$. What is the increase in potential energy of the system when $q_2$ is moved towards $q_1$ by a distance $x$? $(x < d)$ (where $\frac{1}{4 \pi \varepsilon_0} = K$ is a constant).

An electric charge $10^{-6} \mu C$ is placed at the origin $(0,0) \text{ m}$ of an $X-Y$ coordinate system. Two points $P$ and $Q$ are situated at $(\sqrt{3}, \sqrt{3}) \text{ m}$ and $(\sqrt{6}, 0) \text{ m}$ respectively. The potential difference between the points $P$ and $Q$ will be:

Draw a graph for the variation of electrostatic potential $V$ with distance $r$ from a point charge $Q$.

$A$ charge of total amount $Q$ is distributed over two concentric hollow spheres of radii $r$ and $R$ $(R > r)$ such that the surface charge densities on the two spheres are equal. The electric potential at the common centre is