Why Is The Electric Field Inside A Conductor Zero

The net electric field inside a conductor is always zero. So, there is no electric field lines inside a conductor. In this article, I will explain why the net electric field line inside a conductor is always zero.

In conductor , electrons of the outermost shell of atoms can move freely through the conductor. These electrons are called free electrons.

Now, let an external electric field E is applied on the conductor. So, there will be some electric field line inside the conductor.

If a charge q is put inside an electric field, an electric force F will be applied on it .

F = q*E

If the charge is negative, the direction of the electric force will be opposite to the direction of the electric field E. So, if an external electric field E is applied on a conductor, each free electron will feel an electric force F opposite to the direction of E.

As the free electrons can move freely inside the conductor, the electrons will move to the left side of the conductor . Thus , there will be a net negative charge on the left side and a net positive charge on the right side.

This distribution of charges will generate an electric field Eᵢ inside the conductor.

As long as the external electric field E is stronger than Eᵢ , electrons will keep moving towards left generating more positive charge on the right side and more negative charge on the left side. Thus Eᵢ will be stronger . When both E and Eᵢ will be equal in magnitude, the net electric field inside the conductor will be zero and no other electron will move to left. This is the electrostatic condition. So, finally there will be no net electric field inside the conductor and thus, there will be no electric field line inside any conductor.

For non conductor , there is no free electron , so no charge can be moved inside a non conductor. Thus applying an electric field on a non conductor will generate an electric field inside the non conductor.