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
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{\left( {R - r} \right)Q}}{{\left( {{R^2} + {r^2}} \right)}}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{\left( {R + r} \right)Q}}{{2\left( {{R^3} + {r^3}} \right)}}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{\left( {R + r} \right)Q}}{{\left( {{R^2} + {r^2}} \right)}}$
$\frac{1}{{4\pi {\varepsilon _0}}}\frac{{\left( {R - r} \right)Q}}{{2\left( {{R^2} + {r^2}} \right)}}$
Some charge is being given to a conductor. Then its potential is
A thin spherical conducting shell of radius $R$ has a charge $q$. Another charge $Q$ is placed at the centre of the shell. The electrostatic potential at a point $p$ at distance $\frac{R}{2}$ from the centre of the shell is
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 $\left( {\frac{1}{{4\pi { \in _0}}} = k} \right).$
$64$ identical drops each charged upto potential of $10\,mV$ are combined to form a bigger dorp. The potential of the bigger drop will be $..........\,mV$
A spherical conductor of radius $2m$ is charged to a potential of $120\, V$. It is now placed inside another hollow spherical conductor of radius $6m$. Calculate the potential to which the bigger sphere would be raised......$V$