electricity

Asked by  | 8th Dec, 2008, 04:55: PM

Expert Answer:

A permanent magnet is one that stays magnetized. Materials which can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic. These include iron, nickel, cobalt, some rare earth metals and some of their alloys, and some naturally occurring minerals such as lodestone. The other type of magnet is an electromagnet, a coil of wire which acts as a magnet when an electric current passes through it, but stops being a magnet when the current stops. Often an electromagnet is wrapped around a core of ferromagnetic material like steel, which enhances the magnetic field produced by the coil. Permanent magnets are made from "hard" ferromagnetic materials which are designed to stay magnetized, while "soft" ferromagnetic materials like soft iron are attracted to a magnet but don't tend to stay magnetized.

Answered by  | 10th Dec, 2008, 11:01: PM

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