How is the electric field inside a conductor?

The electric field inside a conductor is zero.

When an electric field is applied to a conductor, the free electrons inside the conductor move to cancel out the field. This redistribution of charge creates an electric field inside the conductor that is equal and opposite to the external field. As a result, the net electric field inside the conductor is zero.

This phenomenon is known as electrostatic shielding and is the reason why conductors are used to protect sensitive electronic equipment from external electric fields. The absence of an electric field inside a conductor also ensures that charges on the surface of the conductor are uniformly distributed.

It is important to note that the electric field inside a conductor is only zero in electrostatic equilibrium. If the external electric field changes, the charges inside the conductor will redistribute themselves to cancel out the new field, and a non-zero electric field may briefly exist inside the conductor before reaching a new equilibrium state.

In summary, the electric field inside a conductor is zero in electrostatic equilibrium due to the redistribution of charges inside the conductor to cancel out the external field.