Magnet: the term
magnet is derived from magnetite (Fe3O4) which is an ore
Any substance which possesses the following two properties is
called a magnet.
1. It attracts
small pieces of iron towards itself.
suspended freely, it always comes to rest in the north-south direction.
and artificial magnets:
Lode stone and Magnetite are natural magnets because they are
found in nature.
Artificial magnets are prepared by man to be used at any time
and at any place. These magnets are much stronger than lode stone.
Example: soft iron
and non magnetic substances:
Substances which are attracted by a magnet are called
Example: Iron, Cobalt, Nickel etc.
Substances which are not attracted by a magnet are called
Example: paper, cloth
of a magnet: The two ends of a magnet where the magnetic force is
greatest are called poles of magnet. Each magnet has two poles. The end of the
magnet that points towards the north is called North Pole. And the other end of
the magnet pointing towards the south is called South Pole.
poles repel, unlike poles attract.
For Example take two bar magnets. Suspend one magnet with a piece
of thread. It will come to rest in the north-south direction. Hold the other
magnet in your hand and bring its north pole near the north pole of the suspended
magnet. You will find that the north pole of the suspended magnet is repelled
that is North Pole moves away.
Now bring the south pole of the magnet in the hand of the
north pole of the suspended magnet. You will find that the north pole of the
suspended magnet will be attracted towards the south pole of other magnet. This
states that like poles repels and unlike poles attract.
poles always exist in pairs:
If a bar magnet is broken into two pieces you will see that
each piece behaves as a whole magnet. This shows that new poles are formed at
the broken ends.
If these pieces are further broken into smaller pieces, each piece
behaves as a whole magnet with two opposite poles.
Thus, we see that even the smallest piece of magnet has north
and south poles and we cannot separate the two poles.Therefore we conclude that Magnetic poles always exist in