Induction, in physics, a process by which a magnetized or electrically charged object produces magnetism, an electric charge, or an electric voltage in another object without being in contact with it. The process is called magnetic induction when magnetism is produced, electrostatic induction when an electric charge is produced, and electromagnetic induction when an electric voltage is produced.
An object capable of being magnetized becomes a magnet when placed near a permanent magnet or a wire carrying an electric current. The magnetization of an iron core in an electromagnet is a result of magnetic induction.
An electric conductor becomes electrified when placed near an electrically charged object. For example, when a charged rod is brought near an electrically neutral conductor, the side of the conductor near the charged rod acquires a charge opposite that of the rod, while the far side acquires the same charge as the rod.
An electric voltage occurs in an electric conductor that is either (1) in motion relative to a magnet or (2) in a changing magnetic field produced by a changing electric current. An electric generator produces a current because of electromagnetic induction.