The maximum electric field that can be held in air without producing ionization of air is $10^7\,V/m$. The maximum potential,therefore,to which a conducting sphere of radius $0.10\,m$ can be charged in air is:

$A$ charge of $10^{-9} \, C$ is placed on each of the $64$ identical drops of radius $2 \, cm$. They are then combined to form a bigger drop. Find its potential.

The radius of a soap bubble whose potential is $16\,V$ is doubled. The new potential of the bubble will be.....$V$

Equal charges are given to two spheres of different radii. The potential will

The diagram shows a small bead of mass $m$ carrying charge $q$. The bead can freely move on a smooth fixed ring placed on a smooth horizontal plane. In the same plane,a charge $+Q$ has also been fixed as shown. The potential at point $P$ due to $+Q$ is $V$. The velocity with which the bead should be projected from point $P$ so that it can complete a circle should be greater than:

$A$ total charge $Q$ is distributed between two concentric spherical shells of radii $r$ and $R$ $(R > r)$ such that their surface charge densities are equal. What is the electric potential at their common center?