Question

Four metal conductors having different shapes are mounted on insulating stands and charged. How many of them is/are best suited to remain the charge for a longer time?

Answer 1

In the case of spherical metal conductor the charge quickly spreads uniformly over the entire surface.

While in case of non-spherical surfaces, the charge concentration is different at different points, in other words surface charge density is high at sharp points and low for broad points.

Due to high charge density at sharp edges, the electric field will be high at these points and nearby particles could be ionised and charge may leak.

Whereas, at the spherical surface, the Electric field will not be that high so no charge will leak, hence it will remain on the surface for longer time.
Hence, option (A) is correct.