Because when a patch is attached to the N and S poles of a magnet, its magnetic force will be reflected to the side when disturbed, and this magnetic force will be greater than that of the N and S poles without iron plate.

Magnets can be regarded as a regular arrangement of small magnetic needles (that is, adjacent small magnetic needles are attracted by different magnetic poles, which is known from Ampere's theory of magnetic origin-molecular current hypothesis). Breaking a magnet is equivalent to separating a small magnetic needle somewhere. After separation, the magnetism of the two places is still different, that is, different magnetic poles appear at the fracture, and the magnetism of the other two ends remains unchanged.

Extended data

Magnet type:

Shape magnets: square magnets, tile magnets, irregular magnets, cylindrical magnets, ring magnets, disc magnets, bar magnets, magnetic frame magnets.

Performance magnets: Sm-Co magnet, Nd magnet (strong magnet), ferrite magnet, Al-Ni-Co magnet, Fe-Cr-Co magnet.

Industry magnets: magnetic components, motor magnets, rubber magnets, plastic magnets, etc.

Magnets are divided into permanent magnets and soft magnets. Permanent magnets strengthen magnetism, so that the spin of magnetic substances and the angular momentum of electrons are arranged in a fixed direction, while soft magnets are electrified. (It is also a method of magnetizing. ) Soft iron will slowly lose its magnetism after being removed by equal current.

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