An empty thick conducting shell of inner radius $a$ and outer radius $b$ is shown in figure.If it is observed that the inner face of the shell carries a uniform charge density $-\sigma$ and the surface carries a uniform charge density $ '\sigma '$
If the inner surface of the shell is earthed, then identify the correct statement(s)
The potential of both the inner and outer surface of the shell becomes zero
Charge on the outer surface becomes zero
Positive charge flows from the shell to the earth
all of the above
A metallic spherical shell has an inner radius ${{\rm{R}}_1}$ and outer radius ${{\rm{R}}_2}$. A charge $\mathrm{Q}$ is placed at the centre of the spherical cavity. What will be surface charge density on $(i)$ the inner surface, and $(ii)$ the outer surface ?
$A$ and $B$ are concentric conducting spherical shells. $A$ is given a positive charge while $B$ is earthed. Then :-
Two charged spherical conductors of radius $R_{1}$ and $\mathrm{R}_{2}$ are connected by a wire. Then the ratio of surface charge densities of the spheres $\left(\sigma_{1} / \sigma_{2}\right)$ is :
A thin-walled, spherical conducting shell $S$ of radius $R$ is given charge $Q$. The same amount of charge is also placed at its centre $C. $ Which of the following statements are correct ?
A spherical portion has been removed from a solid sphere having a charge distributed uniformly in its volume in the figure. The electric field inside the emptied space is