HONG KONG EXAMINATIONS AUTHORITY
HONG KONG CERTIFICATE OF EDUCATION EXAMINATION 1998
PHYSICS PAPER II
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, check that all the questions are there. Look
for the words 'END OF PAPER' after the last question.
3.
ANSWER ALL QUESTIONS. All the answers should be marked on the
Answer Sheet.
4.
Note that you may only mark ONE answer to each question. Two or more
answers will score NO MARKS.
5.
All questions carry equal marks. No marks will be deducted for wrong
answers.
98-CE-PHY II - 1
-1-
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.
(1998-CE-PHY II - 1)
1.
Which of the following units does not represent energy ?
A.
B.
C.
D.
E.
J
Nm
Ws
Pa m3
kg m s-2
(1998-CE-PHY II - 2)
2.
A car undergoes uniform deceleration along a straight road. Its velocity
decreases from 30 m s-1 to 20 m s-1 after travelling a distance of 100 m.
How much further will the car travel before it comes to a rest ?
A.
B.
C.
D.
E.
50 m
80 m
180 m
200 m
300 m
(1998-CE-PHY II - 3)
3.
A block is pulled by a constant force and moves along a smooth horizontal
surface. Which of the following describes the variations of the acceleration
and momentum of the block during the time when thee force is acting ?
A.
B.
C.
D.
E.
98-CE-PHY II - 2
Acceleration
remains unchanged
remains unchanged
increases
increases
decreases
Momentum
remains unchanged
increases
remains unchanged
increases
increases
-2-
(1998-CE-PHY II - 4)
4.
The velocity-time graph of a car travelling along a straight horizontal road
is shown above. Which of the following graphs shows the variation of the
acceleration a of the car with time t ?
A.
B.
C.
D.
E.
98-CE-PHY II - 3
-3-
(1998-CE-PHY II - 5)
5.
At time t = 0, a table–tennis ball is released from a point above the ground
and bounces several times on the ground. The above graph shows the
variation of the velocity v of the ball with time t. (Note: Velocity pointing
upwards is taken to be positive.) At which of the following points on the
graph does the ball reach its maximum height above the ground after the
first rebound ?
A.
B.
C.
D.
E.
Point P
Point Q
Point R
Point S
Point T
(1998-CE-PHY II - 6)
6.
A broken-down car of mass 1000 kg is pulled by a tow-truck and moves at
a constant velocity 8 m s-1 along a horizontal road. It is known that the
frictional force acting on the car is 500 N. Find the tension in the cable
connecting the truck and the car.
A.
B.
C.
D.
E.
98-CE-PHY II - 4
0N
500 N
8 000 N
8 500 N
10 500 N
-4-
(1998-CE-PHY II - 7)
7.
Two
forces F1 and F2
act on a particle P as shown above. If a third force F3 acts on P to keep it in
equilibrium, find the magnitude of F3.
A.
B.
C.
D.
E.
1.4 N
4.0 N
4.2 N
4.5 N
5.8 N
(1998-CE-PHY II - 8)
8.
A girl in a lift uses a spring balance to measure the weight of an object. The
reading of the spring balance is 10 N when the lift is at rest. When the lift is
moving, the reading of the spring balance becomes 8 N. Which of the
following describes the motion of the lift ?
A.
B.
C.
D.
E.
98-CE-PHY II - 5
moving upwards with a uniform velocity
moving downwards with a uniform velocity
moving upwards with an acceleration
moving downwards with an acceleration
moving downwards with a deceleration
-5-
(1998-CE-PHY II - 9)
9.
Which of the following phenomena can be explained by Newton’s first law
of motion ?
(1)
(2)
(3)
A passenger in a car tends to move forward when the car suddenly
stops.
A coin and a feather fall with the same acceleration in a vacuum.
A gun recoils when it fires a bullet.
A.
B.
C.
D.
E.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1998-CE-PHY II - 10)
10.
A man pulls a 50 kg block up a smooth inclined plane making an angle 30°
with the horizontal as shown above. The inclined plane is 6 m long and the
block is pulled from the bottom of the inclined plane to the top in 30 s. Find
the average useful output power of the man.
A.
B.
C.
D.
E.
98-CE-PHY II - 6
5W
10 W
50 W
87 W
100 W
-6-
(1998-CE-PHY II - 11)
11. A uniform beam of length 3 m and weight 300 N lies on a horizontal ground.
What minimum vertical force must be applied to one end of the beam to
just lift that end off the ground ? (Assume the weight of the beam acts
through its mid-point.)
A.
B.
C.
D.
E.
100 N
150 N
300 N
450 N
900 N
(1998-CE-PHY II - 12)
12.
The diagram above shows a screwjack used in lifting a load. Which of the
following can improve its efficiency ?
A.
B.
C.
D.
E.
98-CE-PHY II - 7
using a longer handle
using a lighter platform
using a heavier base
using a screw with a larger pitch
using a screw with a small diameter
-7-
(1998-CE-PHY II - 13)
13.
An object is placed x cm in front of a concave mirror and a real image is
formed y cm in front of the mirror as shown above. If the object is now
placed y cm in front of the mirror, which of the following statements is/are
correct ?
(1)
(2)
The new image is virtual.
The new image is formed at a distance x cm in front of the mirror.
(3)
The magnification of the new image is
A.
B.
C.
D.
E.
x
y
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1998-CE-PHY II - 14)
14. A magnifying glass is used to read some small print in a book. Which of the
following statements is correct ?
A.
B.
C.
glass.
D.
E.
98-CE-PHY II - 8
The magnifying glass is a concave lens.
The image of the small print is real.
The object distance is greater than the focal length of the
The image distance is shorter than the object distance.
The small print and its image are on the same side of the glass.
-8-
(1998-CE-PHY II - 15)
15. If F and F´ are the foci of the concave lens, which of the following ray
diagrams is incorrect ?
A.
B.
C.
D.
E.
98-CE-PHY II - 9
-9-
(1998-CE-PHY II - 16)
16.
A
beam consisting of read and violet light travels in a glass block with an air
cavity. The cavity is in the shape of a prism as shown above. Which of the
following diagrams best shows the subsequent path of the beam ?
A.
B.
C.
D.
98-CE-PHY II - 10
-10-
E.
98-CE-PHY II - 11
-11-
(1998-CE-PHY II - 17)
17. Which of the following cannot be an application of the corresponding
optical device ?
Optical device
A.
B.
C.
D.
E.
Converging lenses
Triangular prisms
Convex mirrors
Concave mirrors
Plane mirrors
Application
Spectacles for correcting short sight
Binoculars
Rear view driving mirrors
Reflectors for car headlights
Periscopes
(1998-CE-PHY II - 18)
18. Which of the following phenomena is/are caused by the refraction of light?
(1)
(2)
(3)
If a man who is spear-fishing aims his spear at where the fish appears
to be, he will miss it.
A spectrum is formed when white light passes through a prism.
A light ray is transmitted through a curved glass fibre.
A.
B.
C.
D.
E.
98-CE-PHY II - 12
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
-12-
(1998-CE-PHY II - 19)
19. Which of the following statements about internal energy, heat and
temperature is/are true ?
(1)
(2)
(3)
The internal energy of a body is a measure of the total kinetic energy
and potential energy of the molecules in the body.
Two bodies of the same temperature always have the same amount of
internal energy.
Heat is a measure of the energy transferred from one body to another
as a result of temperature difference between the two bodies.
A.
B.
C.
D.
E.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1998-CE-PHY II - 20)
20.
The above set-up can be used to find the specific latent heat of fusion of ice.
Which of the following is not an essential precaution to ensure an accurate
result ?
A.
using crushed ice in the experiment
B.
using meting ice in the experiment
C.
inserting the immersion heater into the ice completely
D.
using the same amount of ice in both funnels
E.
covering the funnels with lids
(1998-CE-PHY II - 21)
98-CE-PHY II - 13
-13-
21.
The above graph shows the variation of the temperature of a liquid with
time when the liquid is heated by a 400 W heater. The mass of the liquid is
2 kg. Find the specific heat capacity of the liquid. Assume all the energy
given out by the heater is absorbed by the liquid.
A.
B.
C.
D.
E.
83 J kg-1 K-1
480 J kg-1 K-1
1 200 J kg-1 K-1
2 400 J kg-1 K-1
12 000 J kg-1 K-1
(1998-CE-PHY II - 22)
22. A block of melting ice with mass 0.02 kg is put into a polystyrene cup
containing 0.3 kg of water with initial temperature 20℃. After the mixture
is stirred well, the ice block melts completely and the final temperature of
the water becomes 14℃. Which of the following equations can be used to
find the specific latent heat of fusion of ice, L ?
(Given : Specific heat capacity of water = 4200 J kg-1 K-1 )
A.
0.3 x 4200 x 6 = 0.02 L
B.
0.3 x 4200 x 6 = 0.02 L – 0.02 x 4200 x 6
C.
0.3 x 4200 x 6 = 0.02 L + 0.02 x 4200 x 6
D.
0.3 x 4200 x 6 = (0.02 L + 0.02 x 4200 ) x 14
E.
0.3 x 4200 x 6 = 0.02 L + 0.02 x 4200 x 14
(1998-CE-PHY II - 23)
98-CE-PHY II - 14
-14-
23.
Which of the following can increase the average kinetic energy of the
molecules of a fixed mass of gas ?
(1)
(2)
(3)
increasing the volume of the gas at constant pressure
increasing the pressure of the gas at constant volume
increasing the pressure of the gas at constant temperature
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(1998-CE-PHY II - 24)
24.
The above diagram shows a mechanical model of a gas. The ball bearings
are set into motion by a motor-driven vibrating platform. Which of the
following statements is/are correct if the operating voltage of the motor is
increased ?
(1)
(2)
(3)
The disc rises to a higher level.
The average speed of the ball bearings increases.
The average spacing between the ball bearings increases.
A.
B.
C.
D.
E.
98-CE-PHY II - 15
(2) only
(3) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
-15-
(1998-CE-PHY II - 25)
25.
The diagram above shows a series of plane water waves travelling from a
shallow region to a deep region of water. Which of the following diagrams
best shows the wave pattern in the deep region ?
98-CE-PHY II - 16
-16-
(1998-CE-PHY II - 26)
26. A series of plane water waves travel towards an obstacle in a ripple tank.
When the waves pass the obstacle, they bend around the corners of the
obstacle. Which of the following statements is/are correct ?
(1)
(2)
(3)
The phenomenon is called diffraction.
The speed of the waves remains unchanged as they bend around the
corners.
The degree of bending of the waves depends on the size of the
obstacle relative to the wavelength of the waves.
A.
B.
C.
D.
E.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1998-CE-PHY II - 27)
27.
A vibrator generates a stationary wave on a string. The above diagram
shows the string at the instant of maximum displacement. Which of the
following statements is incorrect ?
A.
B.
C.
D.
E.
98-CE-PHY II - 17
Particles P and Q move with the same amplitude.
The motions of particles P and Q are in phase.
Particle Q is momentarily at rest at this instant.
Particle R always remains at rest.
The wavelength of the stationary wave is 0.4 m.
-17-
(1998-CE-PHY II - 28)
28. Which of the following statements about ultrasonic waves is correct ?
A.
B.
C.
D.
E.
They are transverse waves.
They are electromagnetic waves
They travel with a speed of 3 x 108 m s-1 in air.
They cannot travel through a vacuum.
They can be used to sterilize drinking water.
(1998-CE-PHY II - 29)
29.
Three insulated uncharged metal spheres X, Y and Z are placed in contact as
shown above. A negatively charged rod is brought near X and sphere Y is
then earthed momentarily. If the charged rod is still near X, Which of the
following describes the charges on X, Y and Z ?
A.
B.
C.
D.
E.
98-CE-PHY II - 18
Sphere X
Sphere Y
Sphere Z
positive
positive
positive
zero
zero
zero
zero
positive
zero
negative
zero
negative
positive
zero
negative
-18-
(1998-CE-PHY II - 30)
30.
In
the above circuit,
the reading of the ammeter is 0.4A. Find the resistance of the resistor R.
A.
B.
C.
D.
E.
3Ω
5Ω
6Ω
9Ω
12 Ω
(1998-CE-PHY II - 31)
31.
A motor is connected in series with a 10 Ω resistor and a 12 V power
supply as shown above. If the current in the circuit is 0.5 A, find the power
consumed by the motor.
A.
B.
C.
D.
E.
98-CE-PHY II - 19
3.5 W
5W
6W
7W
14 W
-19-
(1998-CE-PHY II - 32)
32.
The above diagram shows the cross-section of three parallel straight wires
X, Y and Z. X and Y carry currents flowing out of the paper and Z carries a
current flowing into the paper. What is the direction of the resultant force
acting on Y ?
A.
towards the left
B.
towards the right
C.
upwards
D.
downwards
E.
into the paper
(1998-CE-PHY II - 33)
33.
An electrical appliance is connected to a power supply of voltage V by long
connecting wires of total resistance R as shown in the above circuit. It is
found that the current passing through the appliance is only
I0
, where I0
2
is the current required for the appliance to work at its rated value. Which of
the following changes could increase the current through the appliance to
I0 ?
Total resistance of connecting
Voltage of power supply
wires
A. increases to 2 V
increases to 2 R
B. increases to 2 V
remains unchanged
R
2
C.
increases to 2 V
reduces to
D.
remains unchanged
increases to 2 R
98-CE-PHY II - 20
-20-
E.
98-CE-PHY II - 21
reduces to
remains unchanged
-21-
R
2
(1998-CE-PHY II - 34)
34.
In the above diagram, a metal rod is placed inside a magnetic field pointing
into the paper. In which direction should the rod be moved in order to
produce an induced current as shown in the diagram ?
A.
B.
C.
D.
E.
into the paper
out of the paper
upwards
downwards
towards the right
(1998-CE-PHY II - 35)
35. A 4 V a.c. supply is stepped up to 20 V by a transformer. If the current in
the primary coil is 1 A and the power loss of the transformer is 0.8 W, find
the current in the secondary coil.
A.
B.
C.
D.
E.
98-CE-PHY II - 22
0.04 A
0.16 A
0.2 A
0.24 A
0.8 A
-22-
(1998-CE-PHY II - 36)
36.
The above figure shows the display on an oscilloscope with no inputs to the
X- and Y-plates. Which of the following figures best shows the display on
the oscilloscope when an alternating voltage is applied to the X-plates and a
constant d.c. voltage is applied to the Y-plates ?
A.
B.
C.
D.
E.
98-CE-PHY II - 23
-23-
(1998-CE-PHY II - 37)
37.
The following
signals are applied to the
inputs A and B of the above logic gate. (Note : A 5 V denotes a high state
and 0 V denotes a low state.)
Which of the following shows the waveform of the output of the logic
gate ?
98-CE-PHY II - 24
-24-
A.
B.
C.
D.
E.
98-CE-PHY II - 25
-25-
(1998-CE-PHY II - 38)
38.
The above diagram shows a night-time anti-theft device for motor vehicles.
The starter motor of the vehicle would only be ON when switch S is closed
and it is day-time. What device and logic gate do X and Y represent
respectively ?
X
A.
B.
C.
D.
E.
Y
a light emitting diode
a light emitting diode
a light dependent resistor
a light dependent resistor
a thermistor
a NAND gate
a NOR gate
an AND gate
a NOR gate
a NAND gate
(1998-CE-PHY II - 39)
39. A nucleus X emits a beta particle to form a daughter nucleus Y. Which of
the following statements is/are correct ?
(1)
(2)
(3)
X and Y have the same number of neutrons.
The number of protons in X is greater than that in Y by 1.
The total numbers of neutrons and protons in X and Y are equal.
A.
B.
C.
D.
E.
98-CE-PHY II - 26
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
-26-
(1998-CE-PHY II - 40)
40. Which of the following diagrams correctly shows the directions in which α,
β and γ radiations are deflected in a uniform electric field produced by
two charged metal plates ?
A.
B.
C.
D.
E.
98-CE-PHY II - 27
-27-
(1998-CE-PHY II - 41)
41.
In a factory producing aluminium sheets of 1 mm thickness, a thickness
gauge is used to monitor the thickness of aluminium sheets. Which of the
following states the correct radioactive source to be used in the thickness
gauge and the reason behind ?
Source
A.
α
B.
α
C.
β
D.
β
E.
γ
98-CE-PHY II - 28
Reason
α particles have strong ionizing
power and can be easily detected.
The amount of α particles passing
through aluminium depends on its
thickness.
The amount of β particles passing
through aluminium depends on its
thickness.
β particles are less harmful to human
beings.
γ radiation has the greatest
penetrating power.
-28-
Directions :
A.
Each question below (Questions 42-45) 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-E
according to the following table :
1st statement
True
B.
True
C.
D.
E.
True
False
False
2nd statement
True
2nd statement is a correct explanation of
the 1st statement
True
2nd statement is not a correct explanation
of the 1st statement
False
True
False
1st statement
(1998-CE-PHY II - 42)
42. Visible light is a wave.
2nd statement
Visible light can travel through a
vacuum.
(1998-CE-PHY II - 43)
43. The temperature of a pool of
water changes slowly even when
the
temperature
of
the
surroundings changes rapidly.
(1998-CE-PHY II - 44)
44. When hot water is mixed
thoroughly with cold paraffin in a
polystyrene cup, the energy
gained by the paraffin is equal to
the energy lost by the water.
(1998-CE-PHY II - 45)
45. The efficiency of a transformer is
increased if the thickness of the
wires in its coils is reduced.
Water has a high specific heat
capacity.
When hot water is mixed
thoroughly with cold paraffin in a
polystyrene cup, the changes in
temperature of the water and
paraffin are identical.
The energy lost in the coils of a
transformer is reduced if the
thickness of the wires in its coils
is reduced.
END OF PAPER
98-CE-PHY II - 29
-29-
Useful Formulae in Physics
(a)
Relationships between initial velocity u, constant acceleration a, final
velocity v and displacement travelled s after time t :
v  u  at
s  ut 
1 2
at
2
v 2  u 2  2as
(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
(d)
Power = force x velocity
(e)
Equivalent resistance of two resistors R1 and R2 :
(f)
(i)
in series
= R1 + R2
(ii)
in parallel
=
Power
R1 R2
R1  R2
= potential difference x current
98-CE-PHY II - 30
-30-
1 2
mv .
2
1998 Physics Paper II
Question No.
Key
Question No.
Key
1.
2.
3.
4.
5.
E
B
B
B
D
26.
27.
28.
29.
30.
E
A
D
A
C
6.
7.
8.
9.
10.
B
D
D
A
C
31.
72.
33.
34.
35
A
A
B
D
B
11.
12.
13
14.
15.
B
B
D
E
E
36.
37.
38
39.
40.
C
D
D
B
A
16.
17.
18.
19.
20
D
A
C
C
E
41.
42.
43.
44.
45.
C
B
A
C
E
21.
22.
23.
24.
25.
C
E
C
E
A
98-CE-PHY II - 31
-31-