Question

The electric field due to a point charge at a distance r depends according to inverse square law . State how the following quantities depend upon r.
(i) potential due to a point charge
(ii) potential at a distance r from the centre of a charged metallic sphere of radius R (r < R).​

Answer 1

Flux enclosed is not constant since ∫E.ds over a surface of radius r is not constant and is inversely proportional to r. hence (i) is not valid.

Also F=Eq, initially distance r is inverse square in electric field but now distance r is changed to inverse cube in electric field. hence electric field is changed from initial condition, hence a charge will experience a force. hence (ii) is valid.