When the conductor is placed in the electric field E, the free charge in the conductor (the free charge of metal conductor is free electron, and nonmetal may be ion) moves directionally under the action of electric field force; In this way, the two sides of the conductor (along the electric field direction) gather the same amount of different charges (because the net charge of the conductor is zero), so the induced charges on both sides generate an additional electric field E' inside the conductor. With the accumulation of induced charges, the e' inside the conductor increases and the field strength E-E' decreases, which is the electrostatic induction process. When the internal field strength is zero everywhere, the directional motion of the free charge in the conductor stops, and the conductor is said to be in electrostatic equilibrium at this time.

The nature of electrostatic balance: 1, the field strength inside the conductor is zero everywhere, and there is no net charge inside the conductor; 2. The surface of the conductor is equipotential surface, and the conductor is equipotential body;

Electrostatic induction of charged conductor, after the conductor is charged, electrostatic induction occurs under the action of charged electric field, and finally electrostatic balance is achieved. In equilibrium, the net charge is only distributed on the outer surface of the conductor.

If the conductor is connected with other conductors through wires, the net charge will be redistributed after the connection, and they will eventually become the same equipotential body (in electrostatic balance)-grounding is equivalent to treating the earth as a big conductor, and the surface area of the earth can of course be regarded as zero compared with the conductor, which is why an isolated and charged conductor is no longer charged after grounding-all the charges are distributed on a big conductor, and the net charge carried by the conductor itself is regarded as zero.