HONG KONG EXAMINATIONS AUTHORITY
HONG KONG CERTIFICATE OF EDUCATION EXAMINATION 1994
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.
94-CE-PHY II - 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
All the cells are assumed to have negligible internal resistance.
(94-CE-PHY II - 1)
1.
Which of the following is a correct unit for the corresponding physical quantity ?
A.
B.
C.
D.
E.
Physical quantity
Unit
Work
Upthrust
Momentum
Heat capacity
Electromotive force
watt
kilogram
newton second
joule per kilogram
newton
(94-CE-PHY II - 2
2.
A trolley is given a push and runs down a friction-compensated runway. The motion
of the trolley is recorded on the paper tape as shown above. Which of the following
changes can enable the trolley to produce a paper tape as shown below ?
(1)
(2)
(3)
Giving the trolley a harder initial push
Increasing the angle of inclination of the runway
Increasing the frequency of the ticker-tape timer
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 3
3.
A man takes 30 s to walk 80 m towards the east. He then takes 10 s to run 60 m
towards the south. Which of the following statements is/are correct ?
(1)
The magnitude of the resultant displacement of the man is 140m.
94-CE-PHY II - 2
(2)
(3)
The average speed of the man is 4.3 m s-1.
The magnitude of the average velocity of the man is 2.5 m s-1.
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
E.
(1), (2) and (3)
(94-CE-PHY II - 4
4.
Two blocks X and Y of weights 2 N and 8 N respectively are suspended by two
light strings as shown above. A downward force of 4 N is applied to X. Find the
tensions T1 and T2 in the two strings.
A.
B.
C.
D.
E.
94-CE-PHY II - 3
T1
T2
2N
4N
4N
6N
6N
8N
10 N
14 N
12 N
14 N
(94-CE-PHY II - 5)
5.
A solid rectangular block of dimensions 3 cm x 4 cm x 5 cm exerts a pressure P on
a horizontal table when it stands on face X as shown above. What is the pressure
exerted by the block on the table if it stands on face Y?
A.
B.
C.
D.
E.
5
3
5
4
P
4
5
3
5
P
P
P
P
(94-CE-PHY II - 6)
6.
A man of mass 50 kg is standing in a lift. If the lift is falling freely, which of the
following statements is/are true ?
(1)
(2)
(3)
The weight of the man is 0 N.
The force acting on the floor of the lift by the man is 500 N.
The force acting on the man by the floor of the lift is 0 N.
A.
B.
C.
D.
E.
94-CE-PHY II - 4
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 7)
7.
The above diagram shows a light rod under the action of two vertical forces. Under
which of the following conditions will the rod be in equilibrium ?
A.
B.
C.
D.
E.
Applying an upward force of 2 N at P
Applying a downward force of 2 N at P
Applying an upward force of 4 N at R and a downward force of 4 N
at Q
Applying an upward force of 4 N at P and a downward force of 4 N
at R
There is no need to apply any more force as the rod is already in
equilibrium
(94-CE-PHY II - 8)
8.
A screw jack is used to raise a load of 6000 N upwards by 0.3 m. If the efficiency
of the jack is 40%, find the input energy.
A.
B.
C.
D.
E.
94-CE-PHY II - 5
720 J
2400 J
4500 J
8000 J
500001
(94-CE-PHY II - 9)
9.
A stone is projected vertically upwards. Neglecting air resistance, which of the
following graphs shows the variation of the kinetic energy of the stone with the
distance travelled during its upward motion ?
A.
B.
C.
D.
E.
94-CE-PHY II - 6
(94-CE-PHY II - 10)
10.
Two blocks X and Y are connected by a light string passing over a smooth pulley as
shown above. The mass of X is greater than that of Y. The two blocks are released
from rest. Which of the following statements is/are correct ?
(1)
(2)
(3)
The potential energy lost by X is equal to the potential energy gained by Y.
The kinetic energy gained by X is greater than the kinetic energy gained by
Y.
The potential energy lost by X is equal to the sum of kinetic energies gained
by X and Y.
A.
B.
C.
D.
E.
(2) only
(3) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 11)
11.
Which of the following statements concerning real images is/are correct ?
(1)
(2)
(3)
Real images are always diminished.
Real images can be photographed with a camera.
Without a screen, real images cannot be seen by the eye.
A.
B.
C.
D.
E.
94-CE-PHY II - 7
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 12)
12.
In the above diagram, the displacement can is filled with water up to the level of the
spout. The metal block is then completely immersed in the water without it touching
the can. Which of the following statements is/are true ?
(1)
(2)
(3)
The reading of balance A becomes zero.
The reading of balance B increases.
The sum of the readings of balances A, B and C remains unchanged.
A.
B.
C.
D.
E.
(2) only
(3) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 13)
13.
Which of the following devices involve(s) total internal reflection of light as they
work ?
(1)
(2)
(3)
Optical fibres
A prismatic periscope
A microscope
A.
B.
C.
D.
E.
94-CE-PHY II - 8
(2) only
(3) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 14)
14.
A ray of light travels in air and strikes a semi-circular glass block at an angle of
incidence 42. The critical angle of the glass is 42. Which of the following
diagrams best shows the subsequent path(s) of the ray ?
A.
B.
C.
D.
E.
94-CE-PHY II - 9
(94-CE-PHY II - 15)
15.
In the above diagram, the image I of an object O is produced by a concave mirror.
What should the positions of this mirror and its principal focus be ?
Position of mirror
Position of principal focus
Q
R
R
S
T
P
P
Q
R
S
A.
B.
C.
D.
E.
(94-CE-PHY II - 16)
16.
An equal amount of energy is supplied to each of the following substances. Which
one of them will have the smallest rise in temperature ?
A.
B.
C.
D.
E.
94-CE-PHY II - 10
Substance
Mass/kg
Specific heat capacity /J kg-1 K-1
P
Q
R
S
T
1
2
3
4
5
4200
2300
2200
900
480
(94-CE-PHY II - 17)
17.
The above apparatus is used to find the specific latent heat of fusion of ice. Which
of the following is an essential precaution to ensure an accurate result ?
A.
B.
C.
D.
E.
94-CE-PHY II - 11
Crushed ice should be used.
The ice used should be just taken from the refrigerator so that its
temperature is well below 0C.
The amount of ice used in funnel X should be larger than that in Y.
The two funnels should be wrapped in insulating material.
The two beakers should be made of insulating material.
(94-CE-PHY II - 18)
18.
Which of the following graphs correctly shows the relation between the pressure P
and absolute temperature T of a fixed mass of gas at constant volume ?
A.
B.
C.
D.
E.
(94-CE-PHY II - 19)
19.
The pressure of a fixed mass of gas at 30C is 3 x 105 Pa. What would be its
pressure if the volume of the gas is doubled and its temperature is increased to
60C ?
A.
B.
C.
D.
E.
94-CE-PHY II - 12
1.65 x 105 Pa
3.00 x 105 Pa
5.46 x 105 Pa
6.59 x 105 Pa
1.20 x 106 Pa
(94-CE-PHY II - 20)
20.
A vibrator generates a stationary wave on a string. The diagram above shows the
string at the instant of maximum displacement. Which of the following statements is
correct ?
A.
B.
C.
D.
E.
Particle P is moving towards the right.
Particle Q is moving upwards.
Particle R always remains at rest.
Particle S is moving upwards.
All particles in the string move with the same amplitude.
(94-CE-PHY II - 21)
21.
(1)
X-rays
(2)
Ultra-violet rays
(3)
Radio waves
Arrange the above electromagnetic waves in ascending order of frequencies.
A.
B.
C.
D.
E.
(1), (2), (3)
(1), (3), (2)
(2), (1), (3)
(3), (1), (2)
(3), (2), (1)
(94-CE-PHY II - 22)
22.
Which of the following statements concerning infra-red radiation is correct ?
A.
B.
C.
D.
E.
94-CE-PHY II - 13
Infra-red is red in colour.
Infra-red can be detected by a Geiger-Muller counter.
Infra-red can be used to sterilize drinking water.
Infra-red is a longitudinal wave.
Warm objects emit infra-red.
(94-CE-PHY II - 23)
23.
Which of the following is NOT an application of ultrasonics ?
A.
B.
C.
D.
E.
Camera autofocusing
Satellite communication
Measurement of the depth of the sea-bed
Detection of cracks in railway tracks
Examination of foetuses (babies not yet born)
(94-CE-PHY II - 24)
24.
An insulated charged metal rod is brought near an insulated uncharged metal sphere
as shown above. Which of the following can charge the sphere ?
(1)
(2)
(3)
Touching the sphere momentarily with a finger
Touching the sphere momentarily with the rod
Touching the rod momentarily with a finger and then touching the sphere
momentarily with the same finger
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 25)
25.
Which of the following involves the application of electrostatics ?
(1)
(2)
(3)
A photocopier
A precipitator in the chimney of a coal-fired power station
A Van de Graaff generator
A.
B.
C.
D.
E.
94-CE-PHY II - 14
(2) only
(3) only
(1) and (2) only
(1) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 26)
*
26.
A student uses an ammeter and a voltmeter to find the resistance of a light bulb. He
incorrectly connects the circuit as shown above. Which of the following is the most
probable outcome ?
A.
B.
C.
D.
E.
The ammeter burns out.
The voltmeter burns out.
The light bulb burns out.
The reading of the ammeter is zero.
The reading of the voltmeter is zero.
(94-CE-PHY II - 26)
27.
Find the potential difference between X and Y in the above circuit.
A.
B.
C.
D.
E.
*
0V
1V
2V
3V
4V
This item was deleted in the live paper as it was found to be unsuitable.
94-CE-PHY II - 15
(94-CE-PHY II - 28)
28.
In the above circuit, all the light bulbs are identical. What happens to the brightness
of the bulbs L1 , L2 and L3 if switch S is closed ?
L1
A.
B.
C.
D.
E.
decreases
decreases
decreases
remains unchanged
increases
L2
increases
increases
remains unchanged
decreases
remains unchanged
L3
remains unchanged
decreases
remains unchanged
increases
increases
(94-CE-PHY II - 29)
29.
Which of the following diagrams correctly shows the connection of the wires of an
iron to the pins of a plug? (L: Live, N: Neutral, E: Earth)
A.
B.
C.
D.
E.
94-CE-PHY II - 16
(94-CE-PHY II - 30)
30.
Operating voltage 220 V/50 Hz
Power
500W
The above diagram shows the label attached to a rice cooker. Which of the
following statements is/are true when the cooker is working at its rated value ?
(1)
(2)
(3)
The resistance of the cooker is 96.8 .
The cooker draws a current of 4.4 A from the mains supply.
The cooker consumes 1 kW h of electrical energy in 2 hours.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
E. (1), (2) and (3)
(94-CE-PHY II - 31)
31.
Which of the following statements about direct current (d.c.) and alternating current
(a.c.) is/are correct ?
(1)
(2)
(3)
All d.c. sources produce constant voltages.
The direction of current in an a.c. circuit changes with time.
Both d.c. and a.c. produce a heating effect in a resistor.
A.
B.
C.
D.
E.
94-CE-PHY II - 17
(1) only
(2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 32)
32.
Which of the following correctly shows the major energy change in the device when
it is working ?
A.
B.
C.
D.
E.
Device
From
To
A microphone
A loudspeaker
A dynamo
A ticker-tape timer
A transformer
electrical
sound
electrical
electrical
mechanical
sound
electrical
electrical
mechanical
electrical
(94-CE-PHY II - 33)
33.
The above diagram shows three long straight wires X, Y and Z. X and Y carry
currents flowing into the paper while Z carries a current flowing out of the paper.
The currents are all equal in magnitude. What is the direction of the resultant force
acting on X ?
A.
B.
C.
D.
E.
P
Q
R
S
T
(94-CE-PHY II - 34)
34.
100 kW of electrical power is transmitted at 20 kV through cables of total
resistance 4 . Find the potential drop and power loss in the cables.
A.
B.
C.
D.
E.
94-CE-PHY II - 18
Potential drop
Power loss
20 V
20 V
100 V
100 V
20 kV
20 W
100 W
20 W
100 W
100 kW
94-CE-PHY II - 19
(94-CE-PHY II - 35)
35.
In the above circuit, the rating of the light bulb is '40 W, 10 V'. The efficiency of
the transformer is 80%. If the bulb works at its rated value, find the current in the
primary coil.
A.
B.
C.
D.
E.
94-CE-PHY II - 20
0. 16 A
0.2 A
0.25 A
1.6 A
2.5 A
(94-CE-PHY II - 36)
36.
A magnet is initially placed between the ends of a soft iron core as shown above.
The magnet is then quickly rotated clockwise through one complete revolution.
Which of the following statements correctly describes the induced current flowing
through the resistor R ?
A.
B.
C.
D.
E.
94-CE-PHY II - 21
The current flows through R from P to Q, and then reverses its
direction.
The current flows through R from Q to P, and then reverses its
direction.
The current flows through R from P to O.
The current flows through R from Q to P.
There is no current flowing through R.
(94-CE-PHY II - 37)
37.
The above diagram shows the trace of a signal on a CRO with the time base
switched off. The Y-gain is set at 1 V cm-1. Which of the following statements
correctly describes the input signal ?
A.
B.
C.
D.
E.
It is an a.c. of peak voltage I V.
It is an a.c. of peak voltage 2 V.
It is a d.c. of constant voltage 1 V.
It is a d.c. of constant voltage 2 V.
It may be a d.c. of constant voltage 2 V or an a.c. of peak voltage 2
V.
(94-CE-PHY II - 38)
38.
Arrange ,  and  radiation in ascending order of their ionizing powers:
A.
B.
C.
D.
E.
, , 
, , 
, , 
, , 
, , 
(94-CE-PHY II - 39)
39.
Which of the following symbols represents a neutron ?
A.
0
0
n
B.
1
0
n
C.
0
1
n
D.
1
1
n
E.
4
2
n
94-CE-PHY II - 22
(94-CE-PHY II - 40)
40.
Under which of the following conditions would the light emitting diode X in the
above circuit be turned on ?
(1)
(2)
(3)
The environment is dark and S is closed.
The environment is dark and S is open.
The environment is bright and S is closed.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(94-CE-PHY II - 41)
41.
The activity of a radioactive source drops from 640 disintegrations per second to 40
disintegrations per second in 2 hours. Find the half-life of the source.
A.
B.
C.
D.
E.
94-CE-PHY II - 23
7.5 minutes
15 minutes
24 minutes
30 minutes
60 minutes
Directions : 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 :
A.
1st statement
True
2nd statement
True
B.
True
True
C.
D.
E.
True
False
False
False
True
False
2nd statement is a correct explanation of
the 1st statement
2nd statement is not a correct explanation
of the 1st statement
1st statement
2nd statement
(94-CE-PHY II - 42)
42.
When two objects are released
from rest at the same height, the
one with greater mass will take a
shorter time to reach the ground.
(Assume
air
resistance
is
negligible.)
(94-CE-PHY II - 43)
43.
The output energy of a machine is
always greater than the input
energy.
(94-CE-PHY II - 44)
44.
Short sight can be corrected by
concave lens.
(94-CE-PHY II - 45)
45.
When a liquid is boiling, the
average kinetic energy of its
molecules is increasing.
A greater gravitational force will
be acting on the object with
greater mass.
A machine can act as an energy
multiplier.
The image of an object formed by
a concave lens is always erect.
When a liquid is boiling, it
absorbs energy.
END OF PAPER
94-CE-PHY II - 24
Useful Formulae in Physics
(a)
Relationships between initial velocity u, constant acceleration a, final velocity y and
distance travelled s after time r :
v  u  at
s  ut 
1 2
at
2
v  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
=
R1 R2
R1  R2
Power = potential difference x current
94-CE-PHY II - 25
1 2
mv .
2
1994 Physics Paper II
Question No.
Key
Question No.
Key
1.
2.
3.
4.
5.
C
A
B
E
D
*26.
27.
28.
29.
30.
D
C
A
A
C
6.
7.
8.
9.
10.
B
D
C
B
A
31.
32.
33.
34.
75.
D
D
B
B
C
11.
12.
13.
14.
15.
B
B
C
E
C
36.
37.
38.
39.
40.
A
A
E
B
E
16.
17.
18.
19.
20.
C
A
D
A
C
41.
42.
43.
44.
45.
D
D
E
B
D
21.
22.
23.
24.
25.
E
E
B
C
E
94-CE-PHY II - 26