Exercise (Assertion & Reason)

A spherical conducting shell of inner radius $r_1$ and outer radius $r_2$ has a charge $Q$. A charge $q$ is placed at the centre of the shell. Find the surface charge densities on the inner and outer surface of the shell.

Assertion: On going away from a point charge or a small electric dipole, the electric field decreases at the same rate in both cases.

Reason: Electric field is inversely proportional to the square of the distance from the charge in all cases.

Assertion: Electric field inside conductor is zero in electrostatics. 

Reason: Charge appears on surface of conductor.

Assertion: Heart can be considered as dipole.

Reason: Electric flux and electric field are same as dipole.

Assertion: Electric flux density is independent of medium.

Reason: It depends only on distance and charge.

Assertion: For a charged shell, potential inside shell depends only on the field inside shell.

Reason: Potential of shell may be determined only by the field outside.

Assertion :- Electrostatic energy does not follow superposition principle. 

Reason :- Electrostatic energy density is a quadratic function.

Assertion: We cannot find electric field from Gauss's law for unsymmetrical charge distribution.

Reason: Gauss's law is not applicable for unsymmetrical charge distribution.