Magnetism

Magnetism is the property displayed by magnets and produced by the movement of electric charges, which results in objects being attracted or pushed away.

Magnet is a piece of iron or other materials that can attract iron containing objects and that points north and south when suspended.

A magnet is characterized by following two properties:

(i)                  Attractive property: A magnet attracts magnetic substances like iron, cobalt, nickel and some of their alloys like magnetite (Fe₃O₄)

(ii)                Directive property: When a magnet is freely suspended, it alights itself in the geographical north south direction.

A magnet may be (i) Natural (ii) Artificial

Natural magnet is oxide or iron. But due to irregular shape, weak magnetism and high brittleness, natural magnets find no use in the laboratory.

The magnets made by artificial methods are called artificial magnets or manmade magnets. They may be of different types like bar magnet, horse shoe magnet, Robinson’s ball ended magnet, magnetic needle, electromagnet etc.

The two points near the two ends of a magnet where the attracting capacity is maximum are called magnetic poles. When a magnet is freely suspended, its one pole always directs towards the north. This pole is called North Pole. The other pole is called South Pole.

The imaginary line joining the two poles of a magnet is called magnetic axis of the magnet.

Similar poles repel each other and dissimilar poles attract each other.

When a magnetic substance is placed rear a magnet, it gets magnetized due to induction.