Download F5-23-02-01Phy

2000-2001 Mock Examination
F.5 Physics
PAPER I
Date :
Time :
23 – 2 – 2001
8 : 30 - 10:00 am
Instruction :
1.
This paper consists of TWO Sections. Answer ALL questions in Section A and four
questions in Section B.
2.
Some questions contain parts marked with an asterisk (*). In each of these parts, one mark
is allocated to assess candidates’ ability in effective communication.
3.
Take g = 10 ms2.
4.
The last page of this question paper contains a list of physics formulae which you may find
useful.
Section A
(30 marks)
1. In Figure 1A, the image of an illuminated letter ‘F’ formed by a mirror is caught by a screen .
(a) What kind of mirror is being used ? Explain your answer.
[ 2 marks ]
(b) Figure 1B shows the relation between the image distance v and the object distance u.
(i)
Find the magnification of the image
when u= 18 cm.
[ 2 marks ]
(ii) Find the value of u when u = v.
Hence find the focal length of the mirror.
[ 3 marks ]
(iii) State ONE applications of the mirror in (a).
[ 1 marks ]
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F.5 Physics I (2-2001 Mock)
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2. A kettle with 1.6 kg of water is placed on the top of an electric heater at 1000 W. It takes
14 minutes for the temperature of the water to increase from 20oC to 100oC.
3.
(a) the energy released by the heater,
[ 1 mark ]
(b) the energy absorbed by the water during that time.
[ 2 marks ]
(c) Give TWO reasons to account for the difference of values you obtain in (a) and (b).
[ 2 marks ]
*(a) A fixed mass of gas is enclosed in container. Explain in terms of kinetic theory of gas, how the pressure
would be affected if the temperature increased, keeping the volume constant.
[ 4 marks ]
(b) A weather balloon contains 5 m3 of helium at the normal atmospheric pressure of 100 k Pa and a
temperature of 27oC. What will be its volume when it rises to an altitude where the pressure is 80 k Pa
the temperature is 7oC ?
[ 3 marks ]
*4. Figure 4 shows a structure of a
moving coil galvanometer.
A current flows through the coil
along the direction ABCD.
Explain briefly how the
galvanometer measures the current.
Your answer should include a
diagram showing the forces acting
on the coil due to the current.
[ 5 marks ]
5.
Figure 5
In the circuit shown in Figure 5, the light emitting
diode will emit light only when the environment
is dark or switch S is closed.
(a) Write down
(i) the state of input A (high or low) when
the environment is dark,
(ii) the state of input B when S is closed.
[ 2 marks ]
(b) (i)
Write down the state of the output of the logic gate X in each of the following cases (in your
Answer book) :
Case
Input A Input B output (high or low)
1
high
high
?
2
high
low
?
3
low
high
?
4
low
low
?
[ 2 marks ]
(ii) What kind of logic gate X ?
[ 1 mark ]
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F.5 Physics I (2-2001 Mock)
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Section B (60 marks)
Answer any FOUR questions in this Section.
Name : _____________________
Class No. ____________________
If you attempt this question, fill in the details in the above and tie this sheet into your answer book.
6.
A block of mass 2 kg is projected up a smooth inclined plane. After moving a certain distance up the plane
it then slides back to its point of projection. The graph in Figure 6 shows how the kinetic energy of the block
varies with the distance moved during its upward motion.
Figure 6
(a) (i) Read from the graph the initial kinetic energy of the block, and
(ii) Hence deduce its initial velocity of projection.
[ 4 marks ]
(b) What is the greatest distance moved by the block up the inclined plane ?
[ 2 marks ]
(c) (i) Find the slope of the graph and state its unit.
(ii) What physical quantity does the slope of the graph represent ?
[ 4 marks ]
(d) What is the deceleration of the block during its upward motion ?
[ 2 marks ]
(e) On Figure 6, draw the graph of potential energy against distance up the slope.
(Take the potential energy at the starting point as 0.)
[ 3 marks ]
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F.5 Physics I (2-2001 Mock)
7.
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A glass tank is filled with a liquid. A cork is
placed at the mid-point of the tank as shown in
the figure. A vibrator X is moving up and down
at the surface producing straight waves.
(a) Describe the motion of the cork.
[ 1 mark ]
(b) Suggest a simple method of measuring the wavelength of the wave using stroboscope.
[ 3 marks ]
(c) It takes 2 s for the waves generated by X to reach the opposite end AD of the tank. During this time
interval, the vibrator makes 5 ‘up’ and 5 ‘down’.
(i) the frequency,
(ii) the wavelength, and
(iii) the speed of the wave.
[ 6 marks ]
(d) If another vibrator placed at the opposite end AD is also moving in exactly the same way as X,
what will be the change in the amplitude of the movements of the cork ? Explain briefly.
[ 3 marks ]
(e) If the tank is tilted so that A is higher than B and X is moving as before, sketch a diagram to
show the wave from that would be observed when viewed from the side ABCD.
[ 2 marks ]
8.
(a) A moving coil galvanometer has a full scale deflection current of 5 m A and the resistance of coil in
the galvanometer is 200 .
(i)
Find the full scale deflection voltage.
[ 2 marks ]
(ii) With the help of a resistor, the galvanometer can be adapted to measure a voltage up to 15 V.
(1) Should the resistor and galvanometer be connected in series or in parallel ?
(2) Find the resistance of the resistor.
[ 3 marks ]
(iii) Using the other resistor, the galvanometer is adapted to measure a current up to 5 A,
find the resistance of the resistor.
[ 3 marks ]
(b) When 4-coulomb of charges pass through an electric bulb in 2s, 24J of energy is released.
Find :
(i) the energy transferred per coulomb,
[ 2 marks ]
(ii) the potential difference across the bulb ,
[ 2 marks ]
(iii) the current through the bulb,
[ 1 mark ]
(iv) the energy transferred per second.
[ 2 marks ]
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F.5 Physics I (2-2001 Mock)
9.
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A mercury thread is trapped in a uniform bored capillary tube which is used in an experiment to verify
Charles’ law (see Figure 9A). The experiment set-up is shown in Figure 9B.
Figure 9A
Figure 9B
The following data are recorded :
Temperature /oC
20
30
40
50
60
70
80
Length of air column L/mm
136
140
146
152
156
160
166
(a) Name any TWO precautions in this experiment.
[ 2 marks ]
(b) Plot a graph of L (ranging from 0 mm to 180 mm) against  (ranging from 300oC to 100oC).
(You are recommended to use 1 cm represent 10 mm and 2 cm to represent 50oC).
(c) (i)
[ 4 marks ]
Find the intercept of graph on the L-axis and the slop of the graph.
[ 2 marks ]
Hence write down the equation relating L and .
[ 2 marks ]
(ii) What is the ‘absolute zero’ as obtained from the experiment ?
[ 1 mark ]
(d) How does the pressure of the trapped air in the tube change with temperature change ? [ 1 mark ]
(e) Explain in terms of the kinetic theory of matter, the behaviour of Charles’ Law of gas.
[ 3 marks ]
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F.5 Physics I (2-2001 Mock)
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10. Figure 10 shows part of a decay series.
(a) From Figure 10, name the particle which is emitted in each
of the following changes :
(i)
A B
(ii) B  C
[ 2 marks ]
(b) State two nuclides in the series which are isotopes of each
other.
[ 1 mark ]
(c) The final stable nuclide of the series is X, whose atomic
number is 82 and the number of neutrons is 126.
(i)
Find the mass numbers of A and X.
(ii) Find the total number of  particles emitted from A to X.
[ 4 marks ]
(d) Some of the nuclides in Figure 10 also emit -radiation when they decay, however it is impossible
to identify these nuclides from the figure. Explain briefly.
[ 2 marks ]
(e) A G. M. counter is placed 20 cm from a radioactive source which undergoes the decay as shown
in Figure 10. The CORRECTED count rates in three consecutive minutes are 1027, 1011 and 1018
counts per minute respectively.
(i)
What type(s) of radiation emitted by the source can reach the counter ? Explain briefly.
(ii) Explain what is meant by a CORRECTED count rate.
(iii) Explain briefly why the three readings differ from each other.
[ 6 marks ]
****** END OF PAPER ******
F.5 Physics II(22-11-2001)
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5.
(a) A radioactive source emitting -particles is place inside a cloud chamber.
(i) Explain why tracks are formed.
(ii) Very occasionally, right-angle forked tracks are seen as below (Figure 5) when the chamber is
filled with helium gas.
[ 4 marks ]
Figure 5
(b) State ONE applications of radiation .
[ 1 mark ]