Question

Why should electrostatic field be zero inside a conductor?

Answer 1

Hint: We can understand this by learning the behavior of the electrostatic field and its effect on electrons inside a conductor. This can be studied using Faraday's law describing the generation of electric fields by timely variations of magnetic fields and Gauss’s law describing the generation of electric fields due to electric charges.

Complete step by step answer:
When an electrostatic field is applied inside a conductor, the electros start to move in a direction opposite to that of the field and since, in a conductor the valence and conduction bands overlap, the electrons starts to move towards the surface and accumulate there until all the incident field lines start to terminate on the conductor’s surface leaving the inside of conductor free of electrostatic field.
The migration of electrons takes place from one side of a conductor and which results in accumulation of positive charge on that side. The migration of electrons takes place under the influence of the electrostatic field.
Because, the conductors have very high density of free electrons on their surface, the electrostatic field fails to penetrate in it and terminates in a very thin layer on the surface itself. But if the density of mobile charge carriers decreases on the surface, the field can penetrate deeper than usual and this is the reason why in semiconductors, the field is able to reach greater depths.

Note: We can also understand this through another approach by considering a situation, where the electric field is actually able to penetrate inside a conductor. The rearrangements of electrons will take place and the charges will move towards the surface and will again leave a zero field effect inside the conductor.