The work done in carrying a charge $Q$ once around a circle of radius $r$ about a charge $q$ at the centre 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 a distance $R/2$ from the centre of the shell is:

If identical charges $(-q)$ are placed at each corner of a cube of side $b$,then the electric potential energy of charge $(+q)$ which is placed at the center of the cube will be:

In a uniform electric field,the potential is $10 \ V$ at the origin of coordinates,and $8 \ V$ at each of the points $(1, 0, 0), (0, 1, 0)$ and $(0, 0, 1)$. The potential at the point $(1, 1, 1)$ will be....$V$

$A$ small conducting sphere of radius $r$ is lying concentrically inside a bigger hollow conducting sphere of radius $R$. The bigger and smaller spheres are charged with $Q$ and $q$ respectively $(Q > q)$ and are insulated from each other. The potential difference between the spheres will be

$A$ hollow conducting sphere of radius $R$ carries a charge $(+Q)$ on its surface. Find the electric potential at a distance $r = R/3$ from its center.