If the energy stored in a spherical conductor having a charge of $12 \mu \mathrm{C}$ is 6 J , then the radius of the spherical conductor is

Two charged conducting spheres of radii 5 cm and 10 cm have equal surface charge densities. If the electric field on the surface of the smaller sphere is $E$, then the electric field on the surface of the larger sphere is

As shown in the figure, if the values of the electric potential at three points $A, B$ and $C$ in a uniform electric field (E) are $V_A, V_B$ and $V_C$ respectively, then