Two metal spheres $A$ and $B$ of radii $a$ and $b$ $(a < b)$ respectively are at a large distance apart. Each sphere carries a charge of $100 \mu C$. The spheres are connected by a conducting wire,then

$A$ point charge $Q$ is placed inside a cavity within a solid isolated conducting sphere. Consider points $A$, $B$ and $C$, where the magnitudes of the electric fields are $E_A$, $E_B$ and $E_C$, respectively. Point $A$ is inside the material of the conductor. Points $B$ and $C$ are at the same distance from the center of the solid sphere. The correct option is:

$A$ spherical conductor of radius $2 \, m$ is charged to a potential of $120 \, V$. It is now placed inside another hollow spherical conductor of radius $6 \, m$. Calculate the potential to which the bigger sphere would be raised. (in $, V$)

$A$ metallic rod is placed in a uniform electric field. Select the correct option.

$A$ conducting sphere of radius $10\, cm$ is charged with $10\,\mu C$. Another uncharged sphere of radius $20\, cm$ is allowed to touch it for some time. After the spheres are separated,the ratio of the surface charge densities on the spheres will be:

The dimensions of an atom are of the order of an $\mathring{A}$ $(10^{-10} \ m)$. Thus,there must be large electric fields between the protons and electrons. Why,then,is the electrostatic field inside a conductor zero?