Answer to Question #73103 in Electricity and Magnetism for Awais Akhtar

Question

How an electric field inside the conductor is zero?

Answer 1

As we know that, a conductor has a lot of mobile or free electrons, therefore when keep the conductor in an external electric field, electrons will experience a force in the direction opposite to the direction of electric field E and will start accumulating at surface A of the conductor. As electrons are moving opposite to the direction of Electric Field E, positive charge will start building at the opposite face B of the conductor. This accumulation of charge on both surface of conductor A and B, will lead to development of Electric Field E’ inside the conductor and this developed electric field E’ will oppose the flow of further electron toward face A. As the accumulation of electrons increases on the face A, the strength of electric field E’ inside the conductor will also increase and will oppose the flow of electron more strongly. But as soon as the strength of developed electric field becomes equal to the strength of external electric field E, no net electric filed will be there inside the conductor to drive the electrons and hence further accumulation of electrons will stop.
Therefore at equilibrium, developed field E’ is equal to external field E. Therefore, net force on electrons is zero and hence no movement of electrons. Thus we see that at equilibrium, the strength of electric field inside the conductor is zero.