differentiate between temporary and permanent magnet with example
Answers
Permanent Magnets
Permanent magnets differ from temporary magnets by their ability to remain magnetized without the influence of a nearby external magnetic field. Typically, permanent magnets are made from "hard" magnetic materials where "hard" refers to a material's ability to become magnetized and remain magnetized. Steel is an example of a hard magnetic material.
Many permanent magnets are created by exposing the magnetic material to a very strong external magnetic field. Once the external magnetic field is removed, the treated magnetic material is now converted into a permanent magnet.
Temporary Magnets
Unlike permanent magnets, temporary magnets cannot remain magnetized on their own. Soft magnetic materials like iron and nickel will not attract paper clips after a strong external magnetic field has been removed.
One example of an industrial temporary magnet is an electromagnet used to move scrap metal in a salvage yard. An electric current flowing through a coil that surrounds an iron plate induces a magnetic field that magnetizes the plate. When the current flows, the plate picks up scrap metal. When the current stops, the plate releases the scrap metal.
Basic Atomic Theory of Magnets
Magnetic materials possess spinning electrons around an atom's nucleus that individually exert a tiny magnetic field. This essentially makes each atom a tiny magnet within a larger magnet. These tiny magnets are called dipoles because they have a magnetic north and south pole.