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ABC College
2002 – 2003 Mock Examination
Form 5
PHYSICS PAPER 1
Date:
Time:
8: 30a.m. to 11: 00a.m. ( 1
1
hours)
2
This paper must be answered in English
Name: _______________________(________)
Class: ______________
INSTRUCTIONS
1.
Answer ALL questions in Section A and any FOUR questions in Section B.
2.
Write your answers in the answer book provided. For Section A, there is no need to start each
question on a fresh page.
3.
Some questions contain parts marked with an asterisk (*). In answering these parts, candidates are
required to give paragraph-length answers. In each of these parts, one mark is allocated to assess
candidates’ ability in effective communication.
4.
Take g = 10 ms-2.
5.
Unless otherwise specified, numerical answers should be either exact or correct to three significant
figures.
6.
Unless otherwise specified, all the cells are assumed to have negligible internal resistance.
Section A
(30 marks)
Answer ALL questions in this section.
1. The figure shows a ray of blue light entering a
semi-circular glass block in the direction PQ. The
angle of incidence at Q is 30o. The critical angle of
blue light for the glass block is 37o.
Q
30o
P
Glass block
(a) When the ray reaches Q, it splits into two. Copy the figure and sketch the two rays. (Label the
ray of the stronger intensity with S).
(2 marks)
(b) Calculate
(i) the refractive index of the glass block for the blue light.
(2 marks)
(ii) the angle of refraction of the ray on leaving the glass block.
(2 marks)
2.
1 000cm3 of Oxygen at a temperature of 27oC is kept inside a cylinder covered by a piston.
(a) If the pressure of the Oxygen is kept constant, what is the temperature when the gas volume is
doubled.
(3 marks)
(b) If the temperature is increased to 100oC and the pressure is halved, what will be the new
volume of the gas.
(2 marks)
3. A light wooden plank pivoted at O is
used to lift a load of 800N. The effort is
applied at the other end of the plank via a
smooth pulley as shown. The load is
raised through a vertical distance of 6cm.
effort
O
rope
800 N
1.2 m
2m
(a) What is the potential energy gained by the load?
(b) What is the length of the rope has been pulled?
(c) What is the effort required if the efficiency of the system is 100%?
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(2 marks)
(1 mark)
(2 marks)
P
4. Two dots vibrators A and B are attached to the
vibrating arm of a ripple tank. The point Q is in
line with AB. Suppose the vibrator makes 10
oscillations in one second and the wave velocity of
the water in the tank is 20cms-1.
8 cm
6 cm
Q
B

A

4 cm
(a) What is the wavelength of the water waves produced?
(b) What are the path differences at P and Q respectively?
(c) What kind of interference occurs at P and Q respectively?
(2 marks)
(2 marks)
(2 marks)
5. A galvanometer of internal resistance 99 and full
scale deflection 10mA is converted into an
ammeter as shown. The resistance of the resistor R
galvanometer
is 1.
R
(a) Find the current through the resistor R at full scale deflection.
(2 marks)
(b) Find the maximum current that can be measured by the ammeter.
(2 marks)
6. The figure shows the circuit inside an electric
fan.
(a) Name the devices X and Y.
(2 marks)
X
Y
electric
motor
(b) What happens to Y when the external
temperature is high? Explain briefly.
(2 marks)
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Section B
(60 marks)
Answer any FOUR questions in this section. Each question carries 15 marks.
7.
(a) An illuminated object is placed 30cm from a lens. A student at E sees an images on the screen
which has the same size as the object.
(i)
(ii)
(iii)
(iv)
(v)
What kind of lens is?
(2 marks)
State the nature of the image.
(2 marks)
Sketch the image seen by the student.
(1 mark)
What is the focal length of the lens?
(1 mark)
If the lens is accidentally broken into two equal halves, and the upper half is put back to the
lens holder, describe how the image has changed.
(2 marks)
(b) In the figure, a convex lens is placed 10cm in front of an object of height 2cm. AP is the
principle axis of the lens.
5 cm
2 cm
H
Object
A
K
p
q
P
r
If an image of height 6cm is formed on a screen,
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8.
(i)
(ii)
find the magnification of the image,
(2 marks)
copy the diagram into a graph paper and complete the refracted rays of p, q, r and draw the
(iii)
image of HK,
find the image distance and the focal length of the lens.
(3 marks)
(2 marks)
Two identical immersion heaters at the same power rating are put respectively into two well
insulated cups. One cup contains 0.5kg of liquid A while the other contains 0.03kg of liquid B.
After the heaters are switched on, the temperature against time graphs of liquid A and liquid B are
plotted as shown below.
180
160
B
temperature/ oC
140
A
120
100
80
60
40
20
0
0
20
40
60
80
100
120
140
time/ s
(a)
(b)
A student says that the specific heat capacity of liquid B in gaseous state is higher than that in
liquid. Do you agree with him? Explain.
(3 marks)
Determine the boiling point of liquid A and liquid B respectively.
(2 marks)
If the specific heat capacity of liquid A is 1 250 Jkg-1oC-1, find
(i) the power rating of the heater.
(ii) the specific heat capacity of B in liquid state.
(4 marks)
(d) Determine the specific latent heat of vaporization of liquid A.
(2 marks)
(e) Describe briefly the difference in the molecular behaviour of a substance in its liquid and
gaseous states. Hence explain why energy is required to vaporise a substance.
(4 marks)
(c)
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9.
A disc resting on a smooth horizontal table is stunk by a rod as shown in figure A which then moves
to the right. The disc travels along a smooth surface AB and then a rough surface at B. The
speed-time graph of the disc is shown in figure B. PQ denotes the motion of the disc in portion AB
while QR denotes the motion in BC. The mass of the disc is 0.5kg.
speed/ ms-1
4
rod
disc
3
Q
P
2
A
B
C
1
0
1
2
figure A
3
4
R
5
6
time/ s
figure B
(a) If the time of contact between the rod and the disc is 0.2s, find
(i) the momentum of the disc at A,
(ii) the average force acting on the disc by the rod,
(iii) the work done by the rod on the disc.
(b) Find the slope of line QR. State the physical meaning.
(2 marks)
(2 marks)
(2 marks)
(2 marks)
(c) From the graph in figure B, find
(i) the distance travelled, and
(ii) the frictional force
when the disc moves along BC.
(d) Find the total energy used in overcoming friction.
(e) State two factors that would affect the distance travelled in (c)(i).
(2 marks)
(2 marks)
(1 mark)
(2 marks)
10. (a) Electrical power is transmitted from a power station at a.c. voltage to a “220V 1100W”
consumer device. The total resistance of the cable connected to the device is 4. The
consumer device is working under its correct rating.
P
X
4
220 V
480 V
1100 W
Q
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Y
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(i) Find
(1) the resistance, and
(2) the current passing through
the consumer device.
(ii) What is the potential drop across the cable?
(iii) Determine the voltage between terminals X and Y.
(iv) If the transformer is 100% efficient, find
(1) the power input to the primary coil of the transformer, and
(2) the turn ratio of the transformer.
(4 marks)
(1 mark)
(1 mark)
(4 marks)
(b) The transformer is now used to lit a number of “220V 60W” bulbs at their correct ratings with
a 5A fuse installed in the primary coil of the transformer.
P
X
220V
60W
Q
Y
Suppose the resistance of the cable in the case is zero, determine
(i) the a.c. voltage supplied to the primary coil,
(ii) the maximum number of bulbs that can be connected,
(iii) the current through the primary coil.
(1 mark)
(2 marks)
(2 marks)
11. The following results are obtained in an experiment to measure the half-life of a radioactive source.
Time/ min
Total court
rate/ counts
per min
0
5
10
15
20
25
30
35
40
45
50
1500
800
450
25
188
144
121
110
103
100
101
(a) From the above data, estimate the background court rate.
(1 mark)
(b) What is meant of the term background radiation?
(1 mark)
(c) The last court rate measured appears to be unreasonable. Do you think the GM counter did not
work properly?
(2 marks)
(d) Plot a graph of the corrected court rate against time, and hence find the half-life of the
radioactive source.
(5 marks)
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(e) Suppose the original mass of the radioactive source is 24g, how long will it takes for the mass
of the radioactive source to be 3g?
(2 marks)
(f) Describe how can we determine the type of radiation emitted by the source.
(g) State one common use of radioactive radiation in medical field.
END OF PAPER
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(3 marks)
(1 mark)