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A teacher asks students to suggest a method to demagnetise a magnet. Some responses are: A) "dropping a magnet on floor several times" B) "breaking the magnet into 2 halves" C) "heating the magnet" D) "throwing the magnet in water" E) "by hammering it" Which of the following are correct?

A teacher asks students to suggest a method to demagnetise a magnet. Some responses are: A) "dropping a magnet on floor several times" B) "breaking the magnet into 2 halves" C) "heating the magnet" D) "throwing the magnet in water" E) "by hammering it" Which of the following are correct? Correct Answer A, C and E

Concept:

Magnet

  • Any material capable of attracting iron and producing a magnetic field outside of itself is referred to as a magnet.
  • The natural magnet is iron oxide(Fe3O4). It does not have a fixed size.
  • When a magnet is suspended freely, aligns approximately along the geographical N-S line.

Magnetic Field 

  • The area around a magnet in which the effect of the magnet can be felt is called the magnetic field.

Demagnetization

  • To lose or remove magnetic property.

Explanation:

The following methods can be used to demagnetize a magnet:

  • Repeatedly hammering the magnet.
  • Rotating the magnet with an alternating current
  • Repeatedly dropping the magnet on the floor
  • Bringing the magnet's temperature to a very high level.

Hence, option 3 is correct.

Additional Information

Magnetic Lines Of Force

  • Lines of force in a magnetic field are imaginary lines that continuously show the direction of the magnetic field in that place.
  • Properties of Magnetic lines of force
    • ​Two lines of force never intersect.
    • Magnetic force lines always originate from the north pole of a magnet and enter the south pole.
    • Where the magnetic field is strong, the line of force is closer.

Important Points

Types of magnets

Permanent Magnet

  • They're called permanent magnets because once magnetized, they don't lose their magnetic properties.
  • Permanent magnets are commonly used.

Temporary Magnet

  • In the presence of a magnetic field, temporary magnets can be magnetized.
  • These materials lose their magnetic properties when the magnetic field is removed.
  • Examples the temporary magnets, iron nails, and paper clips.

Electromagnets

  • An electromagnet is composed of a coil of wire wound around an iron core.
  • When this material is exposed to an electric current, it generates a magnetic field, which causes it to behave like a magnet.

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