Magnet, Properties of Magnet, Types of Magnets, Uses of Magnets (For CBSE, ICSE, IAS, NET, NRA 2022)

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  • It is a material or object that produces a magnetic field.
  • This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets.

About Magnet

  • A magnet is defined as an object which is capable of producing magnetic field and attracting unlike poles and repelling like poles.
  • It is any material capable of attracting iron
  • By the end of the 19th century all the known elements and many compounds had been tested for magnetism, and all were found to have some magnetic property.
  • The common property was of diamagnetism, the name given to materials exhibiting a weak repulsion by both poles of a magnet.
  • Some materials, such as chromium, showed Para magnetism, being capable of weak induced magnetization when brought near a magnet.
  • This magnetization disappears when the magnet is removed.
  • Only three elements, iron, nickel, and cobalt, showed the property of ferromagnetism that is the capability of remaining permanently magnetized

Properties of Magnet

Properties of Magnet
  • Attractive Property – Magnet attracts ferromagnetic materials like iron, cobalt, and nickel.
  • Repulsive Properties – Like magnetic poles repel each other and unlike magnetic poles attract each other.
  • Directive Property – A freely suspended magnet always points in a north-south direction.
  • When it is dipped in iron filings, the iron filings cling to the end of the magnet as the attraction is maximum at the ends of the magnet. These ends are known as poles of the magnets.
  • Magnetic poles always exist in pairs.
  • Whenever it is suspended freely in mid-air, it always points towards north-south direction. Pole pointing towards geographic north is known as North Pole and the pole pointing towards geographic south is known as South Pole.
  • Like poles repel while unlike poles attract.
  • The magnetic force between the two magnets is greater when the distance between these magnets is lesser.

Types of Magnets

Types of Magnets
  • Permanent magnet
  • Temporary magnet
  • Electromagnets

Permanent Magnet

  • They are those magnets that are commonly used.
  • They are known as permanent magnets because they do not lose their magnetic property once they are magnetized.
  • There are four types of permanent magnets:
    • Ceramic or ferrite
    • Alnico
    • Samarium Cobalt (SmCo)
    • Neodymium Iron Boron (NIB)
  • Ways to demagnetize the permanent magnets:
    • Exposing it to extreme temperatures.
    • Stroking one magnet with the other in an inappropriate manner will reduce the magnetic strength.

Temporary Magnet

  • It can be magnetized in the presence of a magnetic field. When the magnetic field is removed, these materials lose their magnetic property.
  • Iron nails and paperclips are examples of the temporary magnet.

Electromagnets

  • It consists of a coil of wire wrapped around the metal core made from iron.
  • When this material is exposed to an electric current, the magnetic field is generated making the material behave like a magnet.
  • The strength of the magnetic field can be controlled by controlling the electric current.

Uses of Magnets

  • Electromagnets find application in speakers, electric bells, and electric cranes.
  • Magnets are used for the separation of iron filling from other solid mixture.
  • Magnets are used for constructing magnetic needles and mariner՚s compass.
  • Permanent magnets find applications in generators, electric accelerators, and electric motors.

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