Please write your answers in the text box provided. Good luck!
Four metal bars A, B, C and D are hung from a rod as shown below. The north pole of a bar magnet is brought near X, and then Y, of each metal bar.
The table below shows the observations made during the experiment.
Metal Bar
A
B
C
D
Observations
North Pole and X
North Pole and Y
repelled
attracted
nothing happened
(a) Which of the metal bars are magnets?
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(b) Explain your choice in (a).
(c) Which one of the metal bars is not a magnet but made of iron?
Sue conducted several test on materials, A, B, C and D, and tabulated her results below.
ability to stretch
no
yes
breaks easily
when dropped
waterproof
(a) What material could Sue use to make a swimming cap which can keep her hair dry?
(b) Could Sue give a toy made of material A to a baby?
(c) Give a reason for your answer in (b).
rubber ball mineral water milk water vapour bottle
Study the things listed in the box above. Classify them in the table below.
Properties
Definite shape
No definite shape
The "pulling" distance of a magnet is the furthest distance from which it is able to attract a magnetic object. Elaine carried out an investigation to find out the "pulling" distance of 3 different types of magnets.
She recorded the "pulling" distance of the different magnets in the table below.
Results:
Magnet
"Pulling" Distance (cm)
Bar Magnet
2.9
Ring Magnet
0.8
U-shaped magnet
1.7
(a) List the magnets according to their strengths, from the weakest to the strongest. [1]
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(Weakest) (Strongest)
(b) State the relationship between the strength of the magnetic force and the pulling distance of the magnets. [1]
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