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Magnetism

7. A freely suspended bar magnet always points in a discs as shown in Figure
north–south direction. The north pole of a freely 3.11. In the hard disc, the
suspended magnet points in the north direction, magnetic material is coated
and the south pole points in the south direction with aluminium or glass. The
of the Earth. Likewise, the arrow of a compass recorded information can be
FOR ONLINE READING ONLY
needle points towards the north. retrieved by playing back,
using a special head.
Shapes of magnets
Magnetic
Magnets are of different types, and they work in disks
different ways. They differ in materials, shapes,
sizes, functions, forces and applications. For
example, magnets can have different shapes, which
include bar, horseshoe and disc as shown in Figure
3.10. Magnets also vary in size from tiny discs used Housing
in speakers to large magnets used in commercial
power-generating plants. One of the largest magnets Figure 3.11: Magnetic recording
is perhaps the Earth itself. media

2. Credit, debit and ATM
cards
These have a magnetic strip
on one of their sides. This
Horseshoe magnet Bar magnet Ring magnet strip contains the necessary

information to contact an
individual’s financial institution
and connect with their account.
These automatic cash cards
Ball ended Cylindrical Disc Magnet also use magnetic ink to store
magnet magnet magnet Needle
information. Figure 3.12 shows
Figure 3.10: Types of magnets according to their shapes an example of an automatic cash
card.
Applications of magnets Magnetic strip
Magnets are widely used in various electronic
devices, as described in the following examples:

1. Magnetic recording media
Magnetic recording is a technology that stores
information on a magnetic medium. Examples of
magnetic recording media include computer hard Figure 3.12: ATM card

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Physics Form 2 Final.indd 99 25/10/2025 10:26