Magnet: Discovery, Poles and Properties

How magnet was discovered?

  • It is believed that magnets were discovered by Cretan shepherd named Magnes.
  • He was herding his ship when nails in his shoes and his iron rod stuck to the rock he was standing on.
  • Such rocks were given the name Magnetite and this is how natural magnets were discovered.

lodestone
Magnetic and Non Magnetic Materials

attraction of nails

  • Magnetic Materials – Materials which get attracted towards a magnet.
  • Non Magnetic Materials – Materials which do not get attracted towards a magnet.

Poles of Magnet

poles of magnet

  • When steel clips are sprinkled over a magnet, it is observed that the steel clips get attracted to some parts of the magnet more than the others.
  • These parts are known as POLES.
  • We can name the poles as North and South Pole but which pole should we name as North and which to name as South? Read the next topic to understand this.

Finding Directions

rotating the magnate

direction with help of sun

  • The bar magnet is suspended and is rotated.
  • It will again come back to the same position when it comes to rest.
  • It always point in North-South Direction.
  • But how to know which direction is NORTH and which is SOUTH?
  • The sun rises from east and the direction to the left of EAST is NORTH.
  • Now compare this direction with the magnet and you will get all the directions.

Attraction and Repulsion between Magnets

magnet - attraction & repulsion

So what can be infer from above two observations? Can you observe in first figure the two people experience an attractive force while in second figure, they feel a repulsive force.

  • UNLIKE poles attract each other ( N-S)
  • LIKE poles repel each other (N-N, S-S)

Magnetic Compass

magnet - magnetic compass

  • Magnetic compass was used by Sailors to find directions in the wide open oceans and sea.
  • The needle of Magnetic Compass always point in North South direction when it comes to rest.
  • The compass is rotated until the north and south marked on the dial coincides with the needle.

To learn more about Magnets and its properties, download Byju’s the Learning App.


Practise This Question

A steady current i flows in a small square loop of wire of side L in a horizontal plane. The loop is now folded about its middle such that half of it lies in a vertical plane. Let μ1 and μ2 respectively denote the magnetic moments due to the current loop before and after folding. Then