MAGNETISM
The name magnet was
given to a mineral found in magnesia in Asia-Minor. This mineral, a black oxide
of iron had the strange property of attracting small pieces of iron.
Substances
like iron, steel, cobalt and nickel which are attracted by a magnet are called
magnetic substances. Substances like wood, glass, and copper which are not
attracted by a magnet are called non-magnetic substances.
The
three properties of magnets are changing astound usage
One of the familiar
properties of magnets is that attractive. A magnet attracts substances like iron,
cobalt and nickel. The magnet-concentrated ends are known as Poles. This
property was turned into the invention of today’s huge grains.
The well-known property
of a magnet is the North and South Pole direction property. Because earth magnetism
is only that Poles. This thinking of humans by this property was used to invent a compass which is used to predict direction. This property is not only this
usage it’s turned into inventing many devices which want to direction.
The one of best usage
properties of magnets is induction. The property of magnetic induction was to change the total electricity production method. Nowadays all-electric generators are
used by this property.
In 1820 Hans Christian Oersted discovered that a compass needle got deflected when an electric current
passed through a metallic wire placed nearby. So he concludes that when current
passes through any metal it also exerts a magnetic field.
Later Michel Faraday saw an article on Oersted’s magnetic field effect. He thought about
that article how we turn into useful? He would like to do research from the revered
order of Oersted which means when a magnetic field changes that will be induced current. Such research was great to reach worldwide. Because of that research
was useful to electricity generators.
Magnetic substances
Usually, magnets are
three kinds of substances which differ from attraction, strong
attraction and repulsion.
Diamagnetic substances
The substances get
repelled when brought near a strong magnet. These substances are called
dia magnetism. For instance, diamond, gold, silver etc.
Paramagnetic substances
The substance gets
attracted toward the magnet when brought near a magnet. These are called para-magnetic substances. For instance, platinum and aluminium etc.
Ferromagnetic substances
The substances get
strong attraction when brought near a magnet. This is called ferromagnetic
substances. For instance, iron, nickel cobalt etc.
Artificial magnets
Natural magnets have
weak attractive and directive properties and are irregular in shape. Stronger
magnets having regular shapes can be made out of magnetic materials like steel,
alnico etc., by artificial means and these are known as artificial magnets.
Permanent magnets
The magnetic substance
is called permanent magnets because they have high resistivity and
temperature changes.
Magnetic
lines of force
· A line of force is a curve or the path
along which a free isolated north pole would tend to travel when placed in the
magnetic field.
·
Magnetic lines of force will crowd at
the poles since magnetism is concentrated at the poles.
·
Lines of force due to a uniform magnetic
field will be parallel to one another.
·
Lines of force will never intersect.
·
The null or neutral point in a magnetic
field is a point at which the resultant magnetic intensity is zero.
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science