It is a very basic question that, why the materials are becoming magnetised?
I remember a day, when I was giving lesson to my learners and I explained them about the electromagnetic induction. They were so surprised about the magnetic behavior of materials.
Actually in an atom, tiny electrical particles called electrons move around a central nucleus. Each electron has a magnetic effect as it spins and orbits the the nucleus.
|Remember, there is always magnetic field around the moving charge and electric field around the static charge.
In many types of atoms, the magnetic effects of the electrons cancel, but in some they donot, so each atom acts as a tiny magnet.
In an unmagnetised material, the atomic magnets point in a random direction. But as the material becomes magnetised, more and more of its atomic magnets line up with each other.
Together, billions of tiny atomic magnets act as one big magnet.
Steel is used to make permanent magnets because it is hard to magnetise and demagnetise it.
Iron is used to make temporary magnets because iron can be magnetised and demagnetised easily that is why core of transformer is made up of soft iron.
A magnetic material can be demagnetised by hammering or heating it at high temeprature.
Magnets can be used to hold a refrigerator door closed. Can you share five other places where you might find a magnet in use?
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