The magnet can still produce electricity for a long time.
When a metal object coil cuts the magnetic induction line in the magnetic field, a magnetically induced electromotive force (voltage) is generated. From a microscopic point of view, if there is a voltage difference, a current will form and the direction of the current is opposite to that of the electrons. The directional movement of electrons creates an electric current that charges an object.
It couples a paramagnetic material with a closed magnetic circuit to form an open magnetic circuit, a magnetizing coil and an induction coil, and changes the direction of the closed magnetic circuit by adding an alternating voltage to the coil magnetizing. . Electromagnetic induction in the induction coil generates an electromotive force through changes in the open-circuit magnetic field lines caused by changes in the directiwe have closed magnetic field lines.
The electromotive force is generated by electromagnetic induction in the coil. The variation in magnetic flux through the coil produces an induced current. The process of inserting or removing a magnet from a coil can be likened to the process by which a conductor cuts magnetic field lines.
The change in magnetic flux is only the superficial cause of the induced current. The real cause is that the charge in the coil is moved by the Lorentz force. Part of the conductor intersects the magnetic induction lines in the magnetic field, that is, the direction of movement of the conductor in the magnetic field is not parallel to the direction of the magnetic induction lines.