1.02 Magnetic induction.

Magnets have the ability to attract some metallic objects. We call these ferromagnetic materials. The magnet first magnetises the ferromagnetic material by a process called magnetic induction. Then the opposite poles of the permanent magnet and the induced magnet are attracted to each other. This can be demonstrated by using a permanent magnet to pick up some paper clips or iron tacks. The paper clips within the field of the permanent magnet become magnetised and they align to form a chain, with their opposite poles attracted to each other. The principle can be demonstrated with other ferromagnetic components, such at iron tacks.

Magnetic induction

Hard and soft magnetic materials

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If the magnet is removed, then the chain of tacks would immediately fall apart. However the paper clips would still be attracted to each other and therefore still remain in a chain.. Some magnetic materials loose their induced magnetism when the magnet is removed, these materials are called soft magnetic materials. Other materials retain their magnetism to become permanent magnets themselves, these are called hard magnetic materials. Both of these types of materials have their respective uses in engineering and technology.

Hard and soft magnetic materials