Page 116 - Physics_Form_2
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Physics for Secondary Schools
slide the cylindrical magnet into the test pole of a small magnet points when
tube as shown in Figure 3.31. located at that point, as illustrated
4. Put the bottle cap on. Turn the bottle on using arrows in Figure 3.32.
its side and rotate it.
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Bottle cap
Cylindrical
magnet
Figure 3.32: Magnetic field lines
Test tube around a bar magnet
Plastic The lines of force point away
bottle from the north pole of a magnet
and towards the south pole. The
Iron filings direction at any point along a line
of force is therefore defined as the
Figure 3.31 path that a magnetic north pole
Questions would tend to take. The north end of
a compass needle could also point
(a) What did you observe in the procedure in the same direction as shown in
of part I above? Sketch the pattern. Figure 3.33.
(b) What is your observation in the procedure
of part II?
(c) Explain your observations.
Magnetic lines of force
Recall that iron filings become aligned in the
presence of a magnetic field. This alignment Figure 3.33: Compass needle direction
displays the lines of force in a magnetic field. around a bar magnet
The magnetic lines of force emerge from the
north (N) pole to the south (S) pole of a magnet. Properties of magnetic lines of
They are crowded together or become denser force
at the poles of a magnet, showing that the Some of the properties of magnetic
magnetic field is strong at the poles. Away from lines of force are as follows:
the poles, the field is weak, hence, magnetic 1. Magnetic lines of force are
lines formed are less dense. Magnetic lines of continuous and always form
force show the direction of the magnetic force. closed loops.
The direction of the magnetic lines of force at 2. Lines of force from the bar
any point is the direction in which the north magnet leave the north pole
110
Student’s Book Form Two
Physics Form 2 Final.indd 110 25/10/2025 10:26
