7.1.1 Poles of a Magnet

In this lesson, we will explore the characteristics of magnet poles, the forces they exert on each other, and the distinction between permanent and induced magnets.

Magnetic Poles

The poles of a magnet are the regions where the magnetic forces are strongest.

• A magnet has two distinct poles: a north pole (N) and a south pole (S).
• When two magnets are brought close together, they exert forces on each other.

Attraction and Repulsion

• Like Poles: When two magnets with the same polarity (N-N or S-S) are brought close together, they repel each other. This repulsion is a result of the magnetic forces between like poles.
• Unlike Poles: When two magnets with opposite polarities (N-S) are brought close together, they attract each other. This attraction occurs due to the magnetic forces between unlike poles.

Non-Contact Force

The attraction and repulsion between magnetic poles exemplify non-contact forces, as they occur without direct physical contact between the magnets.

Permanent Magnets

A permanent magnet is a material that possesses its own magnetic field without the need for an external influence. Permanent magnets maintain their magnetism over time and can produce a magnetic field without any additional assistance.

Induced Magnets

An induced magnet is a material that becomes magnetised when placed in a magnetic field.

• Induced magnetism occurs when the material aligns its magnetic domains with the external magnetic field.
• Induced magnets always exhibit a force of attraction when exposed to a magnetic field.
• However, when removed from the magnetic field, an induced magnet quickly loses most or all of its magnetism.

Differences between Permanent and Induced Magnets

• Permanent magnets generate their own magnetic fields, whereas induced magnets acquire magnetism in the presence of an external magnetic field.
• Permanent magnets retain their magnetism over time, while induced magnets lose their magnetism quickly when removed from the magnetic field.

Conclusion

The poles of a magnet represent the regions of strongest magnetic forces. Permanent magnets generate their own magnetic fields and maintain their magnetism over time. Induced magnets acquire magnetism in the presence of an external magnetic field but quickly lose their magnetism when removed.