GEOLOGY

Detailed explanation-1: -Permanent magnets are those magnets that are commonly used. They are known as permanent magnets because they do not lose their magnetic property once they are magnetised.

Detailed explanation-2: -A permanent magnet is one that retains its magnetic properties for a long period of time. Examples are iron, nickel, cobalt and some rare earth alloys etc.

Detailed explanation-3: -Permanent magnets are artificial magnets that retain their magnetic property even in the absence of an external magnetic field. These magnets are produced from substances like hardened steel and some alloys.

Detailed explanation-4: -A good permanent magnet must have a large spontaneous magnetization in zero field (i.e., a high retentivity) and a high coercive force to prevent its being easily demagnetized by an external field.