In an hydrogen atom, the electron revolves around the nucleus in an orbit of radius $0.53 \times {10^{ – 10}}\,m$. Then the electrical potential produced by the nucleus at the position of the electron is……$V$

Three charges $q, \sqrt 2q, 2q$ are placed at the corners $A, B$ and $C$ respectively of the square $ABCD$ of side $'a'$ then potential at point $'D'$

A non uniformly shaped conductor is charged then at it's sharpest point

Ten charges are placed on the circumference of a circle of radius $R$ with constant angular separation between successive charges. Alternate charges $1,3,5,7,9$ have charge $(+q)$ each, while $2,4,6,8,10$ have charge $(-q)$ each. The potential $V$ and the electric field $E$ at the centre of the circle are respectively

(Take $V =0$ at infinity $)$

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……$V$