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MAGNETISM XII (Class 12) NOTES | NEB NEPAL | MAGNET AND ITS PROPERTIES

MAGNET :

                                           A magnet is a material which has its atoms arranged in such a way that it exhibits attractive and directive characters.

 Properties of Magnet :

 1.) A magnet has attractive property. It can attract ferromagnetic materials like iron, nickel, cobalt and their alloys. The strength of attraction follows the inverse square law.

 Ferromagnetic materials : The substances like iron, below a certain temperature (curie point) can possess magnetization (magnetic property) in the absence of an external magnetic field.  These substances are called ferromagnetic materials. 

 2.) A magnet's strength is concentrated in two poles i.e. North pole and South Pole.

 NOTE:
            Even if we break/cut a magnet, the broken pieces will also have both the poles. A magnet having only a single pole (magnetic monopole) has been theorized but has not been practically observed.

 3.) The north poles of two magnets repel each other and north and south poles of the respective magnets attract each other. The south poles of the magnets also repel each other. Thus, when two magnets are brought closer, unlike poles attract and like poles repel.

 4.) The earth can be considered as a giant bar magnet. The actual north pole of the earth when considered as a magnet, is called as the "south magnetic pole" and the actual south pole is considered as the "north magnetic pole". Thus, when a bar magnet is suspended freely about its center of gravity by a thread, it aligns itself such that the north pole of the bar magnet points to the north magnetic pole and the south pole points to the south magnetic pole of the earth.

 5.) When a bar of iron is placed near a magnet, the iron bar becomes magnetized and gains two poles. It begins to attract small pieces of iron filings, nails, etc. This phenomenon is called magnetic induction.

To learn more about magnets, visit these links.

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