$A$ charge $q$ is distributed uniformly on the surface of a sphere of radius $R$. It is covered by a concentric hollow conducting sphere of radius $2R$. What will be the charge on the outer surface of the hollow sphere if it is earthed?

Two spherical conductors $A$ and $B$ of radii $R_1$ and $R_2$ are charged to the same potential and placed at a distance $d$ apart. If these spheres are connected by a conducting wire,what is the ratio of the magnitudes of the electric fields at the surfaces of $A$ and $B$ in the equilibrium state?

$A$ small conducting sphere is hung by an insulating thread between the plates of a parallel plate capacitor as shown in the figure. The net force on the sphere is

The figure shows a solid conducting sphere of radius $1 \, m$,enclosed by a metallic shell of radius $3 \, m$ such that their centers coincide. If the outer shell is given a charge of $6 \, \mu C$ and the inner sphere is earthed,find the charge on the surface of the inner sphere in $\mu C$.

Two spheres of radius $a$ and $b$ respectively are charged and joined by a wire. The ratio of the electric field at the surfaces of the spheres is

An empty thick conducting shell of inner radius $a$ and outer radius $b$ is shown in the figure. If it is observed that the inner face of the shell carries a uniform charge density $-\sigma$ and the outer surface carries a uniform charge density $+\sigma$, choose the correct statement related to the potential of the shell.