Explain briefly about magnetic field

Asked by Ananyaaqua25 | 26th Jun, 2019, 10:49: PM

Expert Answer:

Magnetic field is the region that surrounds a magnet . Magnets are made by magnetic substances
like iron, cobalt and nickel.
One of the properties of magnet is it attracts other magnetic substances. Unique property of magnet is ,
 when a magnet made in the form of bar is suspended freely, then the axis of bar magnet always
point towards North-South direction. This unique property is used to make mariner's compass to get direction.
This unique property of orienting towards north-south direction is due to earths magnetic flied.
Earth behaves like a magnet as if huge bar magnet is placed at core of earth in north-south direction.
Hence there is magnetic field surrounding earth ( typically order of 10-5 Tesla ) and the suspended bar magnet
is getting aligned with the direction of earth's magnetic field.
From the direction of axis of bar magnet whenit is freely suspended, we define the end of bar magnet towards
north direction as north-pole and other end as south-pole.An other property of magnet is like poles repel each other ,
while unlike poles attract each other.
Magnetism in matter is due to movement of charge carriers. When a current is passing through wire ,
there is movement of charge carrires, hence it produces magnetic field surrounding the wire carryiing current .
A wire loop that carries a current is called magntic-dipole .
In magnetic substances , electrons of atom are spinning on its own axis and also revolving around nucleus.
This movement of electrons makes tiny dipoles in matter. Under normal circumstances magnetic dipoles are
randomly oriented hence magnetic effect is getting cancelled. When magnetic substances are placed in strong
magnetic field , all the tiny dipoles are getting aligned in the direction of external magnetic field.
When external magnetic field is removed , tiny dipoles retain the aligned direction hence
magnetic substances becomes permanent magnet.  
In laboratory , magnet is made by passing current through circular coils of many number of turns.
This circular coil is called solenoid. By placing strong magnetic substances that is known as ferromagnetic
substances in the core of solenoid , strength of magnetic field is enhanced.

Answered by Thiyagarajan K | 21st Sep, 2021, 02:28: PM