Magnetism and Type of Magnets - Param Himalaya

What is Magnetism ?

The property due to which a magnetic substance attracts other magnetic substances like iron pieces towards it , is called magnetism.

The substance which possesses the property of magnetism is called a magnet.

Type of magnets : 

1. Permanent magnets : there are two types of permanent magnets :

Natural magnets : 

Definition: Pieces of naturally occurring substance like lodestone are called natural magnets.

Properties :

(i) Attractive property: They attract small iron pieces towards them.

(ii) Directive property: when suspended freely , a magnets aligns itself in the geographical North - South direction for this reason , the suspended piece is called Lodestone or leading stone.

Limitation: 

(1) They may have irregular shape.

(2) They generally have weak magnetic properties.

Artificial magnets : 

Artificial magnets are made of steel or special alloys like Alnico. These magnets have many small 'Atomic' magnets.

Ordinarily the atomic magnets are oriented in random directions . In this case the substance is unmagnetised.

When such a piece is placed in the North - South direction and hammered , the atomic magnets align themselves in the direction of the earth's magnetic field. They retain this alignment and the piece develops a North (N)  and south (S) pole near it's ends.

Advantage : 

They may be given a desired regular shape.

They are strong in magnetic properties.

Temporary magnets ( Electromagnets ) : 

Electromagnets are based on the magnetic effect of electric current. An electromagnet is usually made by placing a soft iron core .

An electromagnet exhibits magnetic properties only as long as the electric current flows through the solenoid. Hence, Electromagnets are temporary magnets.



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