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Tung Wah Group of Hospitals Kap Yan Directors' College
2012-2013
MOCK EXAMINATION
19 Feb 2013
Time allowed: 2 hours 30 minutes
Total marks: 129
LPK
PHYSICS PAPER 1
This paper must be answered in English
GENERAL INSTRUCTIONS
1.
There are TWO sections, A and B, in this Paper. You are advised to finish Section A in about
60 minutes.
2.
Section A consists of multiple-choice questions in this question paper, while Section B contains
conventional questions printed separately in Question-Answer Book B.
3.
Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to
Section B should be written in the spaces provided in Question-Answer Book B. The Answer
Sheet for Section A and the Question-Answer Book for Section B will be collected
separately at the end of the examination.
4.
The diagrams in this paper are NOT necessarily drawn to scale.
5.
The last two pages of this question paper contain a list of data, formulae and relationships which
you may find useful.
--------------------------------------------------------------------------------------------------------------------------------------------------------
INSTRUCTIONS FOR SECTION A (MULTIPLE-CHOICE QUESTIONS)
1.
Read the instructions on the Answer Sheet carefully. Insert the information required 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 SECTION A’ after the last question.
3.
All questions carry equal marks.
4.
ANSWER ALL QUESTIONS. You should use an HB pencil to mark all your answers on the
Answer Sheet. Wrong marks must be completely erased.
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.
P.1
There are 36 questions. The last two pages of this question paper contain a list of data, formulae and
relationships which you may find useful.
1. Metal blocks P and Q are of the same initial temperature. The ratio of the mass of P to that of Q is 5 : 1. The
ratio of the heat capacity of P to that of Q is 1 : 3. If both blocks absorb the same amount of energy and are
then put into good thermal contact, which of the following statements about the heat flow between the two
blocks is correct? Assume no energy is lost to the surroundings.
A.
B.
C.
D.
Heat will flow from P to Q.
Heat will flow from Q to P.
Heat will first flow from P to Q, and then Q to P.
No heat will flow between the two blocks.
2. Double glazed windows can reduce heat loss from a house because
A.
B.
C.
D.
the heat loss from the house through convection is slowed down by the windows.
glass is a poor conductor of heat.
glass is a better conductor than air.
they trap a layer of air in between which is a good insulator of heat.
3. A gas is cooled under room temperature. Its cooling curve is as shown below. The specific heat capacity of the
gas is 2500 J kg1 C1. If the rate of energy loss of the substance is constant throughout the cooling process,
what is the specific latent heat of vaporization of the substance?
A. 75 kJ kg1
B. 100 kJ kg1
C. 150 kJ kg1
D. 250 kJ kg1
4. The relative masses of oxygen and hydrogen molecules are 32 and 2 respectively. For any given temperature,
the ratio
is given by
A. 1/16
B. 1/4
C. 4
D. 16
5. A rail truck X travels along a level track and collides with a stationary truck Y. The two trucks move together
at the same velocity after the collision. Which line, A to D, in the table states how the total momentum and the
total kinetic energy of the trucks change as a result of the impact?
A.
B.
C.
D.
total momentum
unchanged
unchanged
decreases
decreases
total kinetic energy
unchanged
decreases
decreases
unchanged
P.2
6. The graph shows how the resultant force applied to an object of
mass 2.0 kg, initially at rest, varies with time.
What is the speed of the object after 1.0 s?
A. 2.5 m s–1
C. 7.5 m s–1
B. 5.0 m s–1
D. 10 m s–1
7. A car pulls a trailer of weight 2500 N with a force of 20 N for a
distance of 8 km along a horizontal road. How much work is
done by the car in pulling the trailer?
A. 160 J
B. 20 000 J
C. 160 000 J
D. 20 000 000 J
8. A person weighing 600 N stands on a bathroom scale in a lift. If the bathroom scale shows a reading of 906 N,
which of the following could describe the motion of the lift?
(1) Moving downwards and decelerating at 5 m s-2.
(2) Moving downwards with a constant velocity.
(3) Moving upwards and decelerating at 5 m s-2.
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
9. The diagram shows a disc of diameter 120 mm that can turn about an
axis through its centre.
The disc is turned through an angle of 30o in 20 ms. What is the
average speed (in m s-1) of a point on the edge of the disc during this
time?
A. 0.5
B.  
C 1.5π
D. 2π
10. In Figure (a), a stone is released from rest at a certain height above water. After some time, the stone hits the
water surface. For a short duration immediately after the impact, we can assume the water resistance acting
on the stone to be constant. Figure (b) shows the acceleration-time graph of the stone with upward direction
taken as positive. Which of the following velocity-time graphs best represents the motion of the stone?
P.3
11. A young child of mass 20 kg stands at the centre of a uniform horizontal platform which rotates at a constant
angular speed of 3.0 rad s–1. The child begins to walk radially outwards towards the edge of the platform. The
maximum frictional force between the child and the platform is 200 N. What is the maximum distance from
the centre of the platform to which the child could walk without the risk of slipping?
A. 1.1 m
B. 1.3 m
C. 1.5 m
D. 1.7 m
12. The radius of the Earth is R. The gravitational acceleration near the Earth’s surface is g. An object is at a
height of h above the Earth’s surface. Its acceleration due to gravity is
A. 0.414R
B. 0.5R
C. R
g
. What is h?
2
D. 2R
13. What would the period of rotation of the Earth need to be if objects at the equator were to appear weightless?
Given that the radius of Earth = 6.4 x106 m.
A. 4.5 x 10–2 hours
B. 1.4 hours
C. 24 hours
D. 160 hours
Questions 14 to 15 refer to the following diagram.
14. The diagram shows a ray of light passing through a rectangular glass
block.
Which row below correctly identifies the changes to the properties of
the light as it enters the glass block?
A.
B.
C.
D.
Frequency
no change
no change
increases
increases
Velocity
decreases
increases
increases
no change
Wavelength
decreases
increases
no change
decreases
15. What is the critical angle of the glass?
A. 64.2o
B. 41.8o
C. 39.3o
D. 31.2o
16. The diagram represents water waves of constant wavelength passing through two small openings in a barrier in
a ripple tank.
trough
---------- crest
The statement which best describes the interference and brightness at point P is:
A.
B.
C.
D.
It is constructive and appears bright.
It is constructive and appears dark.
It is destructive and appears bright.
It is destructive and appears dark.
17. Which of the following statements about sound waves is/are correct?
(1) Sound waves require a medium to propagate.
(2) When a sound wave travels in air, the vibrations of air particles are perpendicular to the direction of travel
of the sound wave.
(3) The wavelength of a sound wave increases as the wave travels from air to water.
A. (2) only
B. (1) and (2) only
C. (1) and (3) only
P.4
D. (1), (2) and (3)
18. An object is placed at 20 cm from a concave lens of focal length 5 cm. Find the magnification of the image.
A. 0.20
B. 0.33
C. 4.00
D. 6.67
19. The figure shows a wave travelling along a string. At the instant shown, particle P is moving downwards.
Which of the following deductions is/are correct?
equilibrium position
(1) The wave is moving to the right.
(2) Half a period later, particle Q will be moving upwards.
(3) The maximum displacements of particles P and Q from the equilibrium position are different.
A. (1) only
B. (1) and (2) only
C. (2) and (3) only
D. (1), (2) and (3)
20. The four diagrams show waves of different wavelengths approaching slits of different widths. In which
diagram will the diffraction be the greatest?
21. An elastic string is slightly stretched to a length of 1 m. Both ends of the string are fixed. By giving a
disturbance to the string, a stationary wave is produced on it as shown. P and Q are two particles on the string.
Which of the following statements is correct?
A.
B.
C.
D.
The wavelength of the stationary wave is 1 m.
The speed of the wave along the string is zero.
The two ends of the string are antinode positions.
Particles P and Q vibrate in phase.
22. A beam of monochromatic light is incident normally on a plane transmission grating as shown. The maximum
order of fringes formed is 4. Which of the following is a possible angle θ of the second order bright fringe?
A. 13
B. 25
C. 35
D. 45
23. Which of the following is/are the use(s) of microwaves?
(1) Heat therapy
(2) Satellite communication
(3) Radar
A. (1) only
B. (3) only
C. (1) and (2) only
P.5
D. (2) and (3) only
24. Karen combs her hair. Her comb becomes charged and she puts the comb near small bits of paper without
touching them. Which of the following statements is/are correct?
(1) Karen’s hair is charged.
(2) The bits of paper are charged.
(3) The comb attracts the bits of paper.
A. (1) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
25. What is the acceleration of an electron at a point inside two parallel plates with a potential difference 150 V
and a separation 1 cm?
A. 1.2 x 105 m s–2
B. 1.4 x 1012 m s–2
C. 2.7 x 1014 m s–2
D. 2.6 x 1015 m s–2
26. The electric potential at a distance r from a positive point charge is 45V. The potential increases to 50 V when
the distance from the charge decreases by 1.5 m. What is the value of r?
A. 1.3 m
B. 1.5 m
C. 7.9 m
D. 15 m
27. Which one of the following graphs correctly shows the relationship between potential difference (V) and
current (I) for a filament lamp?
28. In the circuit shown, the three light bulbs are identical. If the switch S is closed,
which of the following statements is/are correct?
(1) The brightness of light bulb L1 increases.
(2) The brightness of light bulb L2 increases by 9 times.
(3) The power delivered by the battery increases.
A. (1) only
C. (2) and (3) only
B. (2) only
D. (1) and (3) only
29. The figure shows the cross-sections of three straight wires A,
B and C. Wires B and C carry currents flowing out of the
paper, and A carries a current flowing into the paper. The
three wires are equidistant from each other, and carry
currents of equal size. What is the resultant force acting on A?
The effect of the Earth’s magnetic field may be ignored.
A. Towards the left
C. Up
B. Toward the right
D. Down
30. Which of the following statements about Hall effect is/are correct?
(1) Hall effect occurs only in current-carrying semiconductors.
(2) From the sign of Hall voltage in a material, we can determine the sign of charge carriers in the material.
(3) Hall effect can be applied to measure the strength of a steady magnetic field.
A. (1) only
B. (2) only
C. (3) only
D. (2) and (3) only
31. A charged particle is fired between a pair of parallel plates as
shown in the diagram. On leaving the plates, it has been
deflected downwards by 1 unit. A different charged particle,
which has double the charge and four times the mass of the first,
is fired with the same velocity between the plates. It will be
deflected by
A. ¼ unit.
B. ½ unit.
C. 1 unit.
D. 2 units.
P.6
32. The diagram represents two identical coils X
and Y. The planes of both coils are parallel and
their centres lie on a common axis.
Coil Y is connected to a cell, a variable resistor
and a closed switch. Under which of the
following circumstances would a current be
induced in coil X in the same direction as the
current shown in coil Y?
A.
B.
C.
D.
The coils are moved closer together.
The switch is opened.
The resistance of the variable resistor is decreased.
No change is made to the arrangement.
33. The nuclear equation below shows a nuclear fission reaction undergoing in nuclear reactors.
235
92
1
U  X 144
56 Ba  Y  2 0 n
Which of the following can be X and Y?
A.
X
1
0n
90
36
Y
Kr
B.
1
0
n
90
38
Sr
C.
1
1
p
90
36
Kr
D.
1
1
p
90
38
Sr
34. Uranium-235 can undergo the following nuclear fission reaction.
235
92
90
1
U  01 n  37
Rb  144
55 Cs  2 0 n
Given:
mass of one
235
92
mass of one
90
37
U nucleus = 235.0439 u
Rb nucleus = 89.914 80 u
144
55
mass of one Cs nucleus = 143.9321 u
mass of one neutron = 1.008 665 u
What is the energy released during the reaction?
A. 9.38 × 10−22 J
B. 2.81 × 10−11 J *
C. 1.88 × 10−1 J
D. 1.69 × 10-10 J
35. A sample of radioactive element X decays into a stable element Y. Which graph shows the rate of formation of
element Y, RY with time, t?
36. Which of the following statements about nuclear fission and fusion is/are correct?
(1) Both fission and fusion require a neutron to trigger.
(2) Both fission and fusion produce radioactive wastes.
(3) Fusion reactions require high initiating temperature while fission reactions do not.
A. (2) only
B. (3) only
C. (1) and (2) only
END OF SECTION A
P.7
D. (1) and (3) only
Explanations to selected mc
MC
1-5 A D D B B
21-25 D B D B D
1.
6-10
BCAAD
11-15 A A B A C
16-20 B C A B B
26-30 D C C C D
31-35 B B A B C
36 B
mP = 5 mQ, CP = CQ / 3
E = Pt = CP TP = CQ TQ => TP > TQ => TP > TQ
3.
Let the rate be R.
For cooling of gas, R (10) = mc (80-40) = 2500 m (40)
For condensation, R (35-10) = m l
l = 250 kJ kg-1
4.
crmsO2
H 2
2 1



crms H 2
O 2
32 4
5. Since the trucks move off together, this is a completely inelastic collision, KE decreases.
6. At t = 0.4 s, v = u + (F/m) t = 0 + (5/2) (0.5) = 1.25 m/s
At t = 1 s, v = 1.25 + (15/2) (0.5) = 5 m/s
7. Work done = Fs cos  = 20 x 8000 = 160000 J
8. R – mg = ma
906 – 600 = (600/9.81) a
=> a = 5 m s-2
Since R > mg, so the acceleration is upward, so the possible motions are (1) moving upward and accelerating
at 5 m s-2 or moving downward and decelerating at 5 m s-2.
9. v = r = (2/T) r
10. Acceleration is negative and decreases with time, so the slope becomes less steep.
11. Maximum friction = 200 = 20 (3)2 rmax
rmax = 1.11 m
12. g is inversely proportional r2.
15. n = sin 65o / sin 35o = 1.58
c = sin-1 (1/n) = 39.3o
16. P is trough meeting trough, so a bigger trough is formed, the amplitude increases, so constructive interference
takes place. Trough appears dark.
17. Statement 3, sound wave travels faster in liquid such as water than in air.
23. Heat therapy makes use of infrared, not microwave.
25. a = F/m = eE/m = e (V/d) / m = 1.6 x 10-19 x (150/0.01) / 9.1 x 10-31 = 2.64 x 1015 m s-2
26. 45 =
50 =
Q
4π 0 r
Q
4π 0 ( r  1.5)
50 = 45 r / (r-1.5) => r = 15 m
27. R = V/I increases when the temperature increases as current increases.
31. s = (1/2)(F/m) t2 = (1/2)(qE/m) t2  q/m
Now q  2q, m  4m, so s  0.5 s
35. Rate of decay of X decreases with time and so the formation of product Y also decreases with time.