Two metal spheres of radii $R_1$ and $R_2$ are charged to the same potential. The ratio of charges on the spheres is

Draw a graph of $V$ versus $r$ for a uniformly charged spherical shell of radius $R$.

Two conducting spheres of radii $r_1$ and $r_2$ are equally charged. The ratio of their potentials is (potential of $r_1$ to potential of $r_2$):

Two concentric hollow spherical shells have radii $r$ and $R$ $(R \gg r)$. $A$ charge $Q$ is distributed on them such that the surface charge densities are equal. The electric potential at the centre is

Three point charges $+Q$,$+2Q$,and $q$ are placed at the vertices of an equilateral triangle. The value of charge $q$ in terms of $Q$,so that the electrical potential energy of the system is zero,is given by:

The concentric spheres of radii $R$ and $r$ have positive charges $q_{1}$ and $q_{2}$ with equal surface charge densities. What is the electric potential at their common centre?