2009/10 Hong Kong Budding Scientists Award
Science Knowledge Quiz (Secondary Section)
Time allowed: 50 minutes
Part (A) Multiple Choice Questions (30 marks, 1@))
Only selected Multiple Choice Questions are shown below for student reference:
1. Both copper and copper(II) sulphate solution can conduct electricity by charged particles. When
copper(II) sulphate solution conducts electricity, electrolysis takes place and new substances are
formed. However, no chemical changes take place when copper conducts electricity. Which of
the following statements about the charged particles for electrical conduction in the two cases is
true?
A
The charged particles in copper are more stable than those in
copper(II) sulphate solution.
They have different charged particles for electrical conduction.
The charged particles in copper(II) sulphate solution are larger
than those in copper.
The charged particles in copper cannot move but those in
copper(II) sulphate solution can.
B
C
D
2. On a sunny day, some students were lost in a forest.
CANNOT indicate direction?
A
B
C
D
Watching tree annual ring
Watching the Sunlight direction
Watching the vegetation on the hill slope
Watching the flow of water
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Which of the following methods
3. The figure below shows an object to be projected up a smooth inclined plane. Which of the
following graphs shows the relation of speed and time of the object?
A
B
speed
speed
time
time
C
D
speed
speed
time
time
4. Two blocks, X and Y of masses m and 2m respectively, are accelerated along a smooth
horizontal surface when a force F is applied on Y as shown in the diagram.
What is the magnitude of the force exerted by block Y on block X during this acceleration?
A
F
3
B
F
2
C
2F
3
D
F
5. Newton’s third law concerns the forces of interaction between two bodies. Which of the
following statements relating to the third law is NOT correct?
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A
B
C
D
The two forces must be of the same type.
The two bodies must be in equilibrium.
The two forces must be always opposite in direction.
The two forces must act on different bodies.
6. Four identical light bulbs are connected with a cell as shown in the circuit below. How many
light bulbs light up when both switches are closed? Assume all the wires have no resistance.
A
B
C
D
1 light bulb
2 light bulbs
3 light bulbs
4 light bulbs
7. Which of the following statements about dilute hydrochloric acid is/are CORRECT ?
(I)
(II)
(III)
A
B
C
D
It turns litmus paper red.
It reacts with calcium carbonate to give carbon dioxide.
It reacts with copper to give hydrogen.
(I) and (II) only
(I) and (III) only
(II) and (III) only
(I), (II) and (III)
8. A right-angled supporting frame AOB is shown in diagram(a). The surface of AO is rough and it
is in a horizontal position. OB is smooth and is in a vertical position. There are two rings of
equal mass, one passing through AO and the other passing through OB. The two rings are
connected with a string that cannot be stretched and is of negligible mass. If the ring P in
diagram (a) is now moved to the left a bit like diagram (b), what happens to the supporting force
on the ring by the arm AO and the tension on the string before and after the movement?
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N < N’；T > T’
N < N’；T < T’
N = N’；T > T’
N = N’；T < T’
A
B
C
D
9. In a dark room Siu Ming switches on 3 torches which emit red, green and blue light respectively.
When green light from a torch shines on a coloured cart paper, the cart paper appears green.
When blue light from a torch shines on the same coloured cart paper, the cart paper appears blue.
When red light from a torch shines on the same coloured cart paper, the cart paper appears black.
What is the colour of the cart paper?
A
B
C
D
Cyan
Blue
Yellow
Green
10. The chemical formulae of the first three consecutive members of a series of compounds are
HCOOH, CH3COOH and C2H5COOH respectively. Their general formula is probably
A
B
C
D
CnH2nOn
CnH2n+2On
CnH2nO2
CnH2n+1O2
Answers:
Q1
Q2
Q3
Q4
Q5
Q6
Q7
Q8
Q9
Q10
B
D
A
A
B
A
A
C
A
C
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Part (B) Structured-type Questions (20 marks)
1.
A clothing import company has been offered a new type of sweater.
The label says the sweaters are made of 70% wool, 20% polyester and 10% acrylic fibre.
(a) Suggest why the sweaters were made of a mixture of materials, rather than just a single
type of fibre.
(2 marks)
The molecules of wool are made of many smaller molecules linked together. Wool is a
protein, and amino acids are linked together to form proteins.
(b) The company uses a standard test to see how much wool the sweaters actually contain.
The following graph shows how much ammonia is formed from different amounts of
wool in the test.
(i)
0.4 g of ammonia is formed when a sample of the sweater material is tested.
(I) Use the graph to help you find out what mass of wool is in the sample.
(1 mark)
(II) The sample of sweater material is 5 g. What is the percentage of wool in the
sweater material? Show your calculation clearly.
(3 marks)
(ii) Four more samples are taken from different sweaters in the batch, and each is tested.
The results of the percentage of wool in the samples are
43%
46%
48%
47%
(I) Explain how the evidence is improved by testing more than one sample.
(2 marks)
(II) What do these results show about the information on the label on
the sweaters?
(2 marks)
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2 Figure (2a) and Figure (2b) show a wind turbine used to produce electricity. The turbine
blades are turned by the wind and are connected to an electrical generator.
Figure 2a
Figure 2b (Front view)
(a) State the useful energy transformations that occur during the operation of a wind turbine.
(2 marks)
(b) Suggest and explain 3 ways which may increase the power generated by the wind turbine.
(6 marks)
(c) Suggest ONE advantage and ONE disadvantage of using wind to generate
electricity.
(2 marks)
Remarks:
The Committee of the Hong Kong Budding Scientists Award decided not to provide suggested
solutions to the Structured-type Questions.
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