MAGNETISM

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MAGNETISM

Chinese made compass for their navigators by using these rocks with attractive property.

As it was discovered by Magnes, they called it Magnet and also Magnetite.

Magnetite was the ore with attracting property found in that region. Magnetites are natural magnets. They are called magnetic stones.

Natural magnets do not have a definite shape.

When a magnet is freely suspended, it always comes to rest in north- south direction. That is why they are called leading stones or lode stones.

After learning the method of changing the piece of iron into magnet (magnetization) we have been making and using several kinds of magnet. Such man-made magnets are called artificial magnets. Here some of the shapes of artificial magnets that we use in our daily life .1.Bar magnet 2 Horse shoe magnet 3.Ring magnet

Substances that are attracted by magnet are called magnetic substances. Iron, cobalt, nickel are magnetic substances.

Substances that do not get attracted by magnet are called non-magnetic substances. Paper, plastic are called non- magnetic substances.

The ends of a magnet have the strongest magnetic force. They are called poles of the magnet.

A freely suspended magnet always comes to rest in north-south direction. North seeking pole is called north pole. South seeking pole is called south pole.

Like poles repel each other. Unlike poles attract each other

Magnets lose their properties if they are heated or dropped from a height or hit with a hammer

I. Choose the correct answer

1. It is a natural magnet a) Bar magnet b) Magnetite c) Ring magnet d) Horse-shoe magnet

2. An object that is attracted by magnet. a) wooden piece b) plain pins c) eraser d) a piece of paper

3. The people who made mariner’s compass for the first time. a) Indians b) Europeans c) Chinese d) Egyptians

4. A freely suspended magnet always comes to rest in the _____________ direction a) North - east b) South - west c) East - west d) North - south

5. Magnets lose their properties when they are a) used b)stored c) hit with a hammer d) cleaned

6. Mariner’s compass is used to find the a) speed b) displacement c) direction d) motion