Page 118 - Physics_Form_2

Physics for Secondary Schools

Activity 3.8 5. Use your compass to locate a neutral
point.
Aim: To locate the magnetic 6. Repeat Activity 3.8 with the bar
neutral points magnets aligned in the W-E direction

Materials: large sheet of cardboard, (in a line perpendicular to the drawn
FOR ONLINE READING ONLY
tape, two bar magnets, a N-S line).
compass
Questions
Procedure (a) Why did the compass change

1. On the large sheet of cardboard, direction?
draw a line along the N-S direction (b) Could you locate any neutral point
as indicated by a compass needle. on the N–S or E–W lines? Explain.
2. Tape the bar magnets on the board
with their axis along the N-S line as
shown in Figure 3.36. Magnetic shielding
3. Place a compass at point A near Magnetic shielding is the process of
the bar magnet, then record your limiting the flow of magnetic fields
observations. between two locations, or across an
object, by separating them with a barrier

N-S lines made of conductive ferromagnetic
materials. Without a shield, the magnetic
field lines will pass through a region as in
Magnetic N
field line Figure 3.37.
of a bar
magnet Region to be shielded
B
Compass
location
A
Magnetic Figure 3.37: Magnetic field lines through a
field line of a region
bar magnet
Field lines from the north pole cannot be
stopped from moving to the south pole
of a magnet, but they can be redirected.
Figure 3.36
In this case, the channel is a length of
4. Slowly slide the compass along the ferromagnetic material such as soft iron.
N–S line toward point B until the When magnetic field lines reach the iron,
compass needle spins to point in the they flow along it rather than through
opposite direction. Then, record your the magnet itself. Materials that can
observations. redirect magnetic field lines are said to be

112
Student’s Book Form Two

Physics Form 2 Final.indd 112 25/10/2025 10:26