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Physics for Secondary Schools
Use a compass and dip needle to determine Exercise 3.4
the angles of declination and inclination 1. Briefly explain the following terms
at your location.
as applied in magnetism.
(a) A magnetic field.
Applications of the Earth’s magnetic
field (b) A magnetic line of force.
FOR ONLINE READING ONLY
The Earth’s magnetic field has very 2. (a) Draw a magnetic field around
important applications in our daily life. a bar magnet using magnetic
1. It is used by map-readers to find lines of force.
locations of different places. (b) Draw magnetic fields around
2. It gives useful information in the the pairs of magnets shown in
search for minerals. Figure 3.55:
3. Reversals of the Earth’s magnetic field
provide the basis for dating rocks and
sediments.
4. Map-readers with a magnetic compass
can locate the direction of the magnetic (i) (ii)
north using the compass. Figure 3.55
3. The earth is a magnet. Explain.
5. It protects the Earth from cosmic 4. Describe the applications of the
radiation (potentially damaging high- Earth’s magnetic field.
energy particles from the sun).
ICT Corner Chapter summary
Use ICT tools to find your school, the 1. Magnetism was known to the early
nearest hospital, police station, a bus Greeks since 600 BCE.
station or airport, and any mountainous 2. Some materials have magnetic
region. Document each place’s name, properties and can be made into
location, direction from your school permanent (ferromagnetic) magnets
(e.g., north, south-west), and distance in or temporary (paramagnetic)
kilometres. Then, use the “directions” magnets. All magnets have a north
feature to plan a route from your home to pole and a south pole.
each of the identified places, including the 3. Magnets exert a force on some
means of transport you would use (such materials but not on others. The
as walking, driving, or taking a bus) and force is strongest at the poles of
the magnets, and it can act from a
the estimated travel time for each journey. distance.
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Student’s Book Form Two
Physics Form 2 Final.indd 120 25/10/2025 10:27
