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What is the difference between permanent magnet and an electromagnet??

Dear Student
1. Permanent magnet is not so strong, but electromagnet is very strong.

2. The strength of permanent magnet can't be changed, but that of electromagnet can be changed by changing  the number of turns or the amount of current.

3. Permanent magnet has permanent magnetism, but the magnetism in electromagnet is temporary.

4. The polarity of permanent magnet can't be changed, but that of an electromagnet can be changed by changing the position of positive and negative terminals.

Regards

  • 3
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Dear Student,

A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An electromagnet is made from a coil of wire which acts as a magnet when an electric current passes through it.

Regards,
Priya Agrawal.

  • -2
Dear Student,
 

The following is a section from the class 12 study material. Please look at it, it has been explained in a simple language:

Permanent Magnets and Electromagnets

  • The substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.

  • The making of permanent magnets is an old art. One can hold an iron rod in the North−South direction and hammer it repeatedly.

  • One can also hold a steel rod and strike its one end with a bar magnet continually to make it a permanent magnet.

  • An efficient way to make a permanent magnet is to place a ferromagnetic rod in a solenoid and then pass current. The magnetic field of the solenoid magnetises the rod.

  • The material used for making permanent magnets should have high retentivity—so that the magnet is strong, and high coercivity—so that the magnetisation is not erased by stray magnetic fields, temperature fluctuations or minor mechanical damage.

  • Some suitable materials for making permanent magnets are alnico, cobalt steel and ticonal.

Electromagnets

  • The core of an electromagnet is made of ferromagnetic materials, which have high permeability and low retentivity.

  • The most suitable material for making an electromagnet is soft iron.

  • By placing a soft iron rod in a solenoid and passing current, the magnetism of the rod can be increased thousand fold.

  • Electromagnets are used in electric bells, loudspeakers and telephone diaphragms. Giant electromagnets are used in cranes to lift machinery and bulk quantities of iron and steel.


Regards
​​​​​​​

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