1. 2002-CE
PHY HONG KONG EXAMINATIONS AUTHORITY
2 HONG KONG CERTIFICATE OF EDUCATION EXAMINATION 2002
PHYSICS PAPER 2
10.45 am – 11.45 am (1 hour)
Subject Code 170
1. Read carefully the instructions on the Answer Sheet and insert the information
required (including the Subject Code) in the spaces provided.
2. When told to open this book, you should check that all the questions are there.
Look for the words ‘END OF PAPER’ after the last question.
3. All questions carry equal marks.
4. ANSWER ALL QUESTIONS. You should mark all your answers on the
Answer Sheet.
5. You should mark only ONE answer for each question. If you mark more than
one answer, you will receive NO MARKS for that question.
6. No marks will be deducted for wrong answers.
香港考試局 保留版權
Hong Kong Examinations Authority
All Rights Reserved 2002
2002-CE-PHY 2–1

2. There are 45 questions. The last page of this question paper contains a list of
physics formulae which you may find useful.
If necessary, take g = 10 m s–2.
Unless otherwise specified, all the cells are assumed to have
negligible internal resistance.
1. s/m
20
P Q
t/s
0 5
The figure above shows the distance-time graphs of two toy cars P and Q
moving along a linear track. Which of the following statements are correct ?
(1) Car P will reach the 20 m-mark first.
(2) Car P is overtaking car Q at t = 5 s.
(3) The average speed of car P in the first 5 s is smaller than that of
car Q.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
Resultant force
2.
Time
0
The figure above shows the variation of the resultant force acting on an
object with time. What physical quantity does the area of the shaded region
represent ?
A. acceleration
B. change of momentum
C. work
D. power
2002-CE-PHY 2–2 –1–
保留版權 All Rights Reserved 2002

3. 3. A piece of stone is hung from a balloon, which is rising vertically upward. If
the string connecting the stone and the balloon suddenly breaks, which of
the following velocity-time graphs represents the subsequent motion of the
stone ? [Note : Velocity pointing upward is taken to be positive.]
A. B.
v
v
t
t 0
0
C. D.
v
v
t
0
t
0
4. The following are statements written by three students about Newton’s first
law of motion.
(1) A stationary object will remain in a state of rest unless acted on by
an unbalanced force.
(2) An object undergoing uniform motion will maintain its motion
unless acted on by an unbalanced force.
(3) An unbalanced force is required to maintain the motion of an object
at uniform velocity.
Which of the above statements is/are correct ?
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
2002-CE-PHY 2–3 –2– Go on to the next page
保留版權 All Rights Reserved 2002

4. 5. Which of the following objects are under the action of an unbalanced force
at the instant shown in the diagrams ?
(1) a football being kicked by a (2) a parachutist falling with
player uniform velocity
(3) a swinging pendulum bob
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
6.
30°
A block of mass 0.5 kg slides down a rough inclined plane with an
acceleration of 3 m s–2. If the plane is inclined at 30° to the horizontal, find
the friction between the block and the plane.
A. 1N
B. 1.5 N
C. 2.8 N
D. 4N
2002-CE-PHY 2–4 – 3–
保留版權 All Rights Reserved 2002

5. 7. John, of mass 80 kg, is standing on a weighing scale in a lift. At a certain
instant, the reading of the weighing scale is 600 N. Which of the following
statements about John at this instant is/are correct ?
(1) The gravitational force acting on John is 600 N.
(2) The force exerted by the weighing scale on John is 200 N.
John is accelerating downward at a rate of 2.5 m s–2.
(3)
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
8.
A block is projected up a smooth inclined plane. Which of the following
graphs shows the variation of the kinetic energy (K.E.) of the block with its
potential energy (P.E.) during the upward motion ?
A. B.
K.E.
K.E.
0
0
P.E.
P.E.
C. D.
K.E. K.E.
0 0
P.E.
P.E.
2002-CE-PHY 2–5 –4– Go on to the next page
保留版權 All Rights Reserved 2002

6. 9. 60 N
30 N
A block of weight 100 N is placed on a smooth horizontal table. A vertical
force of 60 N and a horizontal force of 30 N are applied to the block as
shown. Find the magnitude of the resultant force acting on the block.
A. 30 N
B. 40 N
C. 50 N
D. 67 N
10.
The figure above shows a flying wheel in an amusement park. The wheel is
of diameter 18 m and carries eight cages. There is only one passenger of
mass 60 kg inside one of the cages. The wheel rotates with uniform speed
and it takes 80 s for the passenger to travel from the bottom to the top of the
wheel. Find the average useful power output of the motor of the wheel.
(60 × 10 × 18) W
A.
60 × 10 × 18
B. ( )W
80
60 × 10 × π × 9
C. ( )W
80
(60 × 10 × π × 9 × 80) W
D.
2002-CE-PHY 2–6 –5–
保留版權 All Rights Reserved 2002

7. 11. (1) (2) (3)
F
F
F
F F
F
A block is initially at rest on smooth horizontal ground. Two forces of
equal magnitude F act on the block. In which of the above cases will
the block remain at rest ?
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
12.
Grace Kitty
0.8 m s–1
Grace and Kitty, of masses 50 kg and 40 kg respectively, stand on light
rollers on a smooth horizontal floor. They are initially at rest with Grace
holding a 2 kg ball. Grace throws the ball to Kitty and moves backward
with a speed 0.8 m s–1 afterwards. After catching the ball, Kitty moves in
the opposite direction as shown above. Which of the following
statements is/are correct ?
The final speed of Kitty is 0.95 m s–1.
(1)
(2) The horizontal momentum of the ball is conserved in this
process.
(3) The total kinetic energy of Kitty and the ball decreases when
Kitty catches the ball.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
2002-CE-PHY 2–7 –6– Go on to the next page
保留版權 All Rights Reserved 2002

8. 13. Receiver
A microwave receiver is installed in front of a concave reflector. At which
position should the receiver be installed in order to ensure the best reception
of microwaves ?
A. at the centre of curvature of the reflector
B. at the focus of the reflector
C. at the pole of the reflector
D. at the mid-point between the pole and the focus of the
reflector
14.
A ray of light travels in air and strikes a glass block as shown above. Which
of the following diagrams best shows the path of the ray ?
A. B.
C. D.
2002-CE-PHY 2–8 –7–
保留版權 All Rights Reserved 2002

9. 15. Which of the following statements about the properties of virtual images
formed in spherical mirrors is incorrect ?
A. Virtual images can be seen by observers.
B. Virtual images always lie behind the mirror.
C. Virtual images are always erect.
D. Virtual images are always magnified.
16.
A man places his spectacles on a book as shown above. What kind of lenses
does he wear and what defect of vision does he have ?
Lenses Defect of vision
A. converging lenses long-sightedness
B. converging lenses short-sightedness
C. diverging lenses long-sightedness
D. diverging lenses short-sightedness
2002-CE-PHY 2–9 –8– Go on to the next page
保留版權 All Rights Reserved 2002

10. (For Questions 17 and 18.) A cup is placed in front of a window, outside which is a
distant building. Two photos P1 and P2 as shown below are taken with the same
single-lens camera.
Photo P2
Photo P1
17. Which of the following ray diagrams correctly shows how the image I of
the cup O is formed by the lens of the camera in photo P1 ?
A. B. I
O O
I
C. D.
O O
I
I
18. Which of the following statements about the two photos must be correct ?
A. In P1, the images of the cup and the building are on
different sides of the lens of the camera.
B. In P1, the image of the cup is real while that of the
building is virtual.
C. On taking P2, the distance between the lens and the film of
the camera is shorter than that on taking P1.
D. After taking P1, the photographer has to move forward in
order to take P2.
2002-CE-PHY 2–10 –9–
保留版權 All Rights Reserved 2002

11. 19. Temperature
0 Time
A certain amount of crushed solid is heated and the variation of its
temperature with time is shown above. If the same heater is used to heat a
smaller amount of the solid, which of the following graphs (in dash lines)
best shows the variation of the temperature of the solid ?
A. B.
Temperature
Temperature
0
0 Time
Time
C. D.
Temperature
Temperature
0
0 Time
Time
2002-CE-PHY 2–11 – 10 – Go on to the next page
保留版權 All Rights Reserved 2002

12. (For Questions 20 and 21.) The specific heat capacity of a metal is measured using
the following method:
Step 2:
Step 1:
Hot metal block
Beaker
Metal block
Cup
Boiling water
Thermometer
Cold water
Heater
A metal block is first immersed in boiling water for some time. The block is then
transferred to a cup of cold water. After a while, the temperature of the water is
measured.
20. The result of the experiment is as follows:
Mass of metal block = 0.8 kg
Mass of water in the cup = 0.3 kg
Initial temperature of water in the cup = 23°C
Final temperature of water in the cup = 38°C
Find the specific heat capacity of the metal (in J kg–1 K–1).
(Given : Specific heat capacity of water = 4200 J kg–1 K–1.)
A. 236
B. 381
C. 622
D. 953
21. The result obtained in Q.20 is found to be higher than the true value of the
specific heat capacity of the metal. Which of the following is a probable
reason ?
A. Some hot water is still adhered to the metal block when
the block is transferred to the cold water.
B. Some energy is lost to the surroundings when the metal
block is transferred to the cold water.
C. Some energy is absorbed by the cup.
D. The temperature of the metal block is still higher than
38°C when the final temperature of the water in the cup is
measured.
2002-CE-PHY 2–12 – 11 –
保留版權 All Rights Reserved 2002

13. 22. y
y0
x
0
The above graph shows the result obtained when an experiment is
performed to study the relation between the pressure and temperature of a
fixed mass of gas at constant volume. Which of the following statements
is/are correct ?
(1) The y- and x-axes denote the pressure and temperature of the gas
respectively.
(2) The slope of the graph denotes the volume of the gas.
(3) The intercept y0 denotes the absolute zero temperature.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
23. Piston
Gas
Cylinder
A column of gas is trapped inside a cylinder. The piston is now pushed
slowly causing the gas to be compressed at a constant temperature. Which
of the following statements about the gas molecules in the cylinder is/are
correct ?
(1) The average speed of the gas molecules increases.
(2) Each gas molecule exerts a greater impact force on the walls of the
cylinder in each collision.
(3) The gas molecules collide more frequently with the walls of the
cylinder.
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
2002-CE-PHY 2–13 – 12 – Go on to the next page
保留版權 All Rights Reserved 2002

14. 24. In a ripple tank experiment, a series of water waves travels towards a
barrier. Which of the following quantities would remain unchanged after
the waves are reflected by the barrier ?
(1) wavelength
(2) frequency
(3) speed
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
25. A wave source generates waves of frequency 50 Hz. How long does it take
for the waves to travel 100 m ?
A. 0.5 s
B. 2s
C. 5000 s
D. It cannot be determined as insufficient information is
given.
26.
Ripple tank
Spongy lining
Opening
Plane water
waves
Which of the following phenomena would be observed when the water
waves pass through the opening in the above set-up ?
A. reflection
B. refraction
C. diffraction
D. interference
2002-CE-PHY 2–14 – 13 –
保留版權 All Rights Reserved 2002

15. 27. Which of the following is/are the reason(s) for not over-using ultra-violet
lamps to produce a suntan effect ?
(1) Ultra-violet radiation is highly penetrating and will damage body
tissue.
(2) Ultra-violet radiation has a strong heating effect and will damage
body tissue.
(3) Over exposure to ultra-violet radiation may cause skin cancer.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
28.
The figure above shows the image of a foetus (a baby not yet born) taken by
a scanner. Which of the following waves should be used in the scanning
process ?
A. infra-red
B. microwaves
C. ultrasonics
D. X-rays
2002-CE-PHY 2–15 – 14 – Go on to the next page
保留版權 All Rights Reserved 2002

16. 29.
Note Y
Note X
The above figures show the CRO displays of two musical notes X and Y.
The settings of the CRO for displaying the two notes are identical. Which
of the following statements are correct ?
(1) Notes X and Y are of different qualities.
(2) Note X is of a higher pitch than note Y.
(3) Note X is louder than note Y.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
30.
A1
3Ω
A
A2
6Ω
A
S
In the above circuit, both ammeters A1 and A2 read 1 A when switch S is
open. Find the readings of the two ammeters when S is closed.
A1 A2
A. 0.5 A 1.5 A
B. 0.67 A 1A
C. 1A 1.5 A
D. 1A 3A
2002-CE-PHY 2–16 – 15 –
保留版權 All Rights Reserved 2002

17. 31.
A plastic ruler is placed close to a stream of running water coming from an
insulated tap. The stream of water is attracted towards the ruler as shown
above. Which of the following statements are correct ?
(1) The ruler carries an electric charge.
(2) The ruler and the running water are attracting each other with
forces of equal magnitude.
(3) Both positive and negative charges are induced on the running
water.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
E. (1), (2) and (3)
F.
32.
R
Q
P
P, Q and R are three parallel straight wires carrying equal currents flowing
out of the paper. R is equidistant from P and Q. What is the direction of the
resultant force acting on R by P and Q ?
→
A.
←
B.
C. ↑
D. ↓
2002-CE-PHY 2–17 – 16 – Go on to the next page
保留版權 All Rights Reserved 2002

18. 33.
V Y
X
Region P
Region Q
I
0
The figure above shows the voltage-current (V-I ) graphs of two resistors X
and Y. Which of the following deductions is/are correct ?
(1) The resistance of X is higher than that of Y.
(2) If X and Y are connected in series, the V-I graph of the combined
resistor will lie in region P.
(3) If X and Y are connected in parallel, the V-I graph of the combined
resistor will lie in region Q.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
34.
6V
L1
L3
L2
Three identical lamps L1, L2 and L3 of ratings ‘6 V, 12 W’ are connected to a
6 V battery as shown above. Which of the following statements is correct ?
A. The potential difference across L2 is 3 V.
B. The current passing through L1 is 2 A.
C. The total power drawn from the battery is 12 W.
D. The total power dissipated in L1 and L2 is smaller than
that in L3.
2002-CE-PHY 2–18 – 17 –
保留版權 All Rights Reserved 2002

19. 35.
V V
A A
2Ω 2Ω
R R
Circuit (1) Circuit (2)
V
A
2Ω R
Circuit (3)
Which of the above circuits can be used to find the resistance of the resistor
R, by taking the ammeter and voltmeter readings ?
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
2002-CE-PHY 2–19 – 18 – Go on to the next page
保留版權 All Rights Reserved 2002

20. 36.
Live
wire
Neutral
wire
If the live and neutral wires of an electric kettle are mistakenly interchanged
inside the plug as shown above, which of the following will happen ?
A. The kettle will not operate.
B. The fuse of the kettle will blow.
C. The metal case of the kettle will still stand at a high
potential even when the switch of the kettle is off.
D. The heating element of the kettle will still stand at a high
potential even when the switch of the kettle is off.
37. Which of the following shows how a moving-coil galvanometer can be
converted into a voltmeter ?
A. B.
1000 Ω 1Ω
C. D.
1Ω
1000 Ω
2002-CE-PHY 2–20 – 19 –
保留版權 All Rights Reserved 2002

21. 38. A B
6V 24 W
C D
20 : 1 step-down
1 : 20 step-up
transformer
transformer
The figure above shows a model power line. An a.c. supply and two ideal
transformers are used to operate a lamp of rating ‘6 V, 24 W’. The total
resistance of the cables AB and CD is 10 Ω. If the lamp operates at its rated
value, find the power loss in the cables.
A. 0.4 W
B. 3.6 W
C. 160 W
D. 1440 W
Starter
39.
switch
M
X
The above diagram shows the circuit of the starter motor of a car. When the
starter switch is closed, a small current flows through device X and a large
current then flows through the motor and starts it. What is device X ?
A. a transformer
B. a reed relay
C. a thermistor
D. a logic gate
2002-CE-PHY 2–21 – 20 – Go on to the next page
保留版權 All Rights Reserved 2002

22. 234
40. A radioactive isotope undergoes a series of decay processes to form
90 Th
206
How many α-particles and β-particles have been
a daughter nuclide 82 Pb .
emitted in this decay process ?
No. of α-particles No. of β-particles
A. 6 7
B. 7 6
C. 7 8
D. 8 7
41. Which of the following particles cannot be deflected by a magnetic field ?
α-particles
A.
β-particles
B.
C. neutrons
D. protons
42. Which of the following is/are application(s) of radioactivity ?
(1) to estimate the age of ancient remains
(2) to kill bacteria in food
(3) to transmit signals over long distances
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
2002-CE-PHY 2–22 – 21 –
保留版權 All Rights Reserved 2002

23. Directions : Each question below (questions 43 – 45) consists of two statements.
Decide whether each of the two statements is true or false. If both
are true, then decide whether or not the second statement is a correct
explanation of the first statement. Then select one option A, B, C or
D according to the following table :
1st statement 2nd statement
A. True True The 2nd statement is a correct explanation of
the 1st statement
B. True True The 2nd statement is not a correct explanation
of the 1st statement
C. True False
D. False True
1st statement 2nd statement
43. Air-cushioned sports shoes can Air-cushioned sports shoes can
reduce the impact force acting on increase the time of impact
the feet during jumping and between the feet and the ground
running. during jumping and running.
44. A transformer can be used to step A transformer can be used to step
up the power of an a.c. supply. up the voltage of an a.c. supply.
45. A lightning conductor can protect a As the lightning conductor and the
building from being damaged by thundercloud carry like charges,
lightning during a thunderstorm. there is a strong repulsion between
them.
END OF PAPER
2002-CE-PHY 2–23 – 22 –
保留版權 All Rights Reserved 2002

24. Useful Formulae in Physics
(a) Relationships between initial velocity u, uniform acceleration a, final
velocity v and displacement travelled s after time t :
v = u + at
12
s = ut + at
2
v 2 = u2 + 2 as
(b) Potential energy gained by a body of mass m when raised through a height
h is mgh.
(c) Kinetic energy of a body of mass m moving with speed v is
12
mv .
2
Power = force × velocity
(d)
(e) Equivalent resistance of two resistors R1 and R2 :
in series = R1 + R2
(i)
R1 R2
in parallel =
(ii)
R1 + R2
Power = potential difference × current
(f)
2002-CE-PHY 2–24 – 23 –
保留版權 All Rights Reserved 2002

25. 2002 Physics Paper 2
Question No. Key Question No. Key
1. A (48) 26. C (87)
2. B (50) 27. B (41)
3. C (42) 28. C (89)
4. C (75) 29. B (63)
5. B (55) 30. C (57)
6. A (57) 31. D (27)
7. B (48) 32. D (42)
8. C (48) 33. B (48)
9. A (17) 34. D (44)
10. B (43) 35. C (46)
11. A (64) 36. D (54)
12. D (21) 37. A (51)
13. B (74) 38. A (28)
14. D (80) 39. B (75)
15. D (61) 40. B (70)
16. D (58) 41. C (84)
17. A (53) 42. C (61)
18. C (53) 43. A (71)
19. C (69) 44. D (60)
20. B (56) 45. C (69)
21. A (19)
22. A (64)
23. B (49)
24. D (74)
25. D (62)
Note: Figures in brackets indicate the percentages of candidates choosing the
correct answers.
2002-CE-PHY 2–25 – 24–
保留版權 All Rights Reserved 2002