Two charged metallic spheres are joined by a very thin metal wire. If the radius of the larger sphere is four times that of the smaller sphere,the electric field near the larger sphere is

Two metal spheres have their radii in the ratio of $4:7$. They are put in contact and a charge $8.8 \times 10^{-7} \text{ C}$ is given to the system. Then they are separated so that each can exert no influence on the other. The potential due to the smaller sphere at $60 \text{ m}$ from it in Volt is

Given below are two statements.
Statement $I$ : Electric potential is constant within and at the surface of each conductor.
Statement $II$ : Electric field just outside a charged conductor is perpendicular to the surface of the conductor at every point.
In the light of the above statements,choose the most appropriate answer from the options given below.

Explain electrostatic shielding with a necessary diagram.

$A$ 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

$A$ charged spherical conductor of radius $R$ is connected momentarily to another uncharged spherical conductor of radius $r$ by means of a thin conducting wire. Then,the ratio of the surface charge density of the first to the second conductor is: