$125$ identical drops each charged to the same potential of $50\;volts$ are combined to form a single drop. The potential of the new drop will be......$V$

Calculate potential on the axis of a ring due to charge $Q$ uniformly distributed along the ring of radius $R$.

Consider three concentric metallic spheres $A, B$ and $C$ of radii $a , b, c$, respectively where $a < b < c$. $A$ and $B$ are connected, whereas $C$ is grounded. The potential of the middle sphere $B$ is raised to $V$, then the charge on the sphere $C$ is

$STATEMENT-1$ For practical purposes, the earth is used as a reference at zero potential in electrical circuits.and

$STATEMENT-2$ The electrical potential of a sphere of radius $R$ with charge $\mathrm{Q}$ uniformly distributed on the surface is given by $\frac{\mathrm{Q}}{4 \pi \varepsilon_0 R}$.

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 $\left( {\frac{1}{{4\pi { \in _0}}} = k} \right).$

A conducting sphere of radius $R$ is given a charge $Q$. The electric potential and the electric field at the centre of the sphere respectively are