Electric potential at a point distant $0.5 \,m$ from a spherical conductor of radius $0.2 \,m$ charged to $+1 \,nC$ is

If the electric potential of the inner sphere is $10\, V$ and that of the outer shell is $50\, V$,then the potential at the common centre is :- (in $, V$)

There are two thin wire rings,each of radius $R$,whose axes coincide. The charges of the rings are $q$ and $-q$. The magnitude of potential difference between the centres of the rings separated by a distance $\sqrt{3} R$ is

Electric charges having the same magnitude $q$ are placed at $x = 1 \, m, 2 \, m, 4 \, m, 8 \, m, \dots$ and so on. If any two consecutive charges have opposite signs but the first charge is necessarily positive,what will be the potential at $x = 0$?

Two concentric conducting spherical shells of radii $30 \, cm$ and $5 \, cm$ are charged. If the outer shell has a charge of $3 \, \mu C$ and the inner shell has a charge of $0.5 \, \mu C$,what is the electric potential on the outer spherical shell?

In the rectangle shown below,two corners have charges $q_1 = -5\,\mu C$ and $q_2 = +2.0\,\mu C$. The work done in moving a charge $q_0 = +3.0\,\mu C$ from $B$ to $A$ is ......... $J$. (Given: $1/4\pi\varepsilon_0 = 10^{10}\,N\cdot m^2/C^2$)