A charge of $10 \,\mu C$ is placed at the origin of $x-y$ coordinate system. The potential difference between two points $(0, a)$ and $(a, 0)$ in volt will be

A neutral spherical copper particle has a radius of $10 \,nm \left(1 \,nm =10^{-9} \,m \right)$. It gets charged by applying the voltage slowly adding one electron at a time. Then, the graph of the total charge on the particle versus the applied voltage would look like

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

Write an equation for potential due to a system of charges

An electric charge $10^{-3}$ $\mu C$ is placed at the origin $(0, 0) $ of $X - Y$ co-ordinate system. Two points $A$ and $B$ are situated at $\left( {\sqrt 2 ,\sqrt 2 } \right)$ and $(2,0)$  respectively. The potential difference between the points $A$ and $B$ will be.......$V$

Two small equal point charges of magnitude $q$ are suspended from a common point on the ceiling by insulating mass less strings of equal lengths. They come to equilibrium with each string making angle $\theta $ from the vertical. If the mass of each charge is $m,$ then the electrostatic potential at the centre of line joining them will be $\left( {\frac{1}{{4\pi { \in _0}}} = k} \right).$