Using Ampere's loop theorem, the closed integral path should have a right-hand spiral relationship with the current direction, otherwise it will be negative. Closed current should be regarded as net current, that is, currents in opposite directions are subtracted and cancelled.

The induced electric field forces the charge in the conductor to move directionally, forming induced electromotive force. The field strength of rotating electric field, that is, the force of rotating electric field on unit positive charge.

According to Faraday's law of induction, the induced electromotive force will appear in the closed circuit because the magnetic field changes with time. The induced electromotive force is equal to the path integral of the electric field along the closed circuit. Charged particles in a closed circuit will feel the electric field, thus generating current.

Extended data:

When the current of the current-carrying conductor changes, it will induce current in the nearby closed circuit. When the magnet moves, a current will be induced in a closed circuit nearby. When moving a closed circuit near a current-carrying wire or magnet, the closed circuit will induce a current.

The changing magnetic field excites a new electric field in its surrounding space, which is called induced electric field or eddy current electric field. The charge in the electric field will be affected by the induced electric field force, which is a non-electrostatic force that produces electromotive force, and the existence of the induced electric field has nothing to do with the existence of the closed circuit.

Baidu encyclopedia-induced electromotive force