If a charged spherical conductor of radius $10\,cm$ has potential $V$ at a point distant $5\,cm$ from its centre,then the potential at a point distant $15\,cm$ from the centre will be

Two equal positive point charges are kept at points $A$ and $B$. What happens to the electric potential while moving from $A$ to $B$ along the straight line connecting them?

Consider three concentric metal shells $A$,$B$,and $C$ with radii $a$,$b$,and $c$ respectively,as shown in the figure $(a < b < c)$. Their surface charge densities are $\sigma$,$-\sigma$,and $\sigma$ respectively. Calculate the electric potential on the surface of shell $A$.

The electric potential of the Earth is taken to be zero because the Earth is a good:

$A$ total electric charge $Q$ is distributed on the surface of a sphere of radius $R$. What is the electrical potential energy of this system?

Two spherical conductors of radii $4 \ cm$ and $5 \ cm$ are charged to the same potential. If $\sigma_1$ and $\sigma_2$ are the respective values of the surface charge density on the two conductors,then the ratio $\sigma_1 : \sigma_2$ is