2021-2022
Mock Exam
PHY
PAPER 2
Name
Kit Sam Lam Bing Yim Secondary School
2021-2022 Mock Examination
Secondary 6
Class
6D
Class No.
Total No. of Pages:
16
PHYSICS PAPER 2
Question-Answer Book
This paper must be answered in English.
Section A
Astronomy and Space Science
INSTRUCTIONS
MCQ:
(1) After the announcement of the start of the examination, you
should first write your name, class and class number in the spaces
provided.
(2) This paper consists of four sections. Each section contains eight
multiple-choice questions and one structured question which
carries 10 marks. Attempt ALL questions in ANY TWO sections.
(3) Write your answers to the structured questions in the ANSWER
BOOK provided. For multiple-choice questions, blacken the
appropriate circle with an HB pencil. You should mark only ONE
answer for each question. If you mark more than one answer, you
will receive NO MARKS for that question.
(4) The Question-Answer Book and Answer Book will be collected
SAPARATELY at the end of the examination.
×1.25 =
LQ:
/ 10
/ 10
Section B
Atomic World
MCQ:
×1.25 =
LQ:
/ 10
/ 10
Section C
Energy and use of energy
MCQ:
×1.25 =
LQ:
/ 10
/ 10
(5) The diagrams in this paper are NOT necessarily drawn to scale.
(6) The last two pages of this Question-Answer Book contain a list of
data, formulae and relationships which you may find useful.
Section D
Medical Physics
MCQ:
(7) No extra time will be given to candidates for filling in the
question number boxes after the ‘Time is up’ announcement .
LQ:
×1.25 =
/ 10
/ 10
Total:
S6 Physics Mock Exam
2021-2022 (Paper 2)
p. 1
Section A : Astronomy and Space Science
Q.1: Multiple-choice questions
1.1 Voyager 1 is a space probe launched by NASA in 1977. In 2021, it is about 154 AU from the Earth. If it continues to
travel with this average speed towards the nearest star Proxima Centauri, which is 4.2 ly away, how long would it
take?
A
B
C
D
A. 38 000 years
B. 76 000 years
C. 152 000 years
D. 223 000 years
1.2 Copernicus and Kepler were famous scientists who supported the heliocentric model of the universe. However, there
were still some differences in their models. Kepler’s model can predict much more accurate results in the motion of
planets, because
A.
B.
C.
D.
Copernicus introduced the concept of epicycle in his model.
Copernicus thought that orbits of planets are circles.
Copernicus thought that orbits of planets are ellipses in general.
Copernicus did not attempt to explain the retrograde motion of planets.
A
B
C
D
1.3 Pluto is a dwarf planet orbiting around the Sun. Its furthest and closest distances from the Sun are 48.9 AU and 29.7
AU respectively. Find its orbiting period.
A.
C.
11.6 years
246 years
A
B. 162 years
D. 342 years
B
C
D
1.4 A meteoroid is moving directly towards a planet of radius R. When it is at a distance 4R from the centre of the planet,
its kinetic energy is K. When it is at a distance 3R from the centre of the planet, its kinetic energy becomes 2K. At
what kinetic energy would the meteoroid hit the surface of the planet? Assume the planet is a uniform sphere.
A.
C.
3K
10K
B.
D.
A
4K
12K
B
C
D
1.5 The apparent magnitudes and absolute magnitudes of two stars are shown in the following table. Which of the
following statements is correct?
star P
star Q
A.
B.
C.
D.
P
P
P
P
apparent
magnitude
2.15
−1.32
is further away from us than Q.
appears brighter than Q on the Earth.
has a higher surface temperature than Q.
emits less light than Q per unit time.
S6 Physics Mock Exam 2021-2022 (paper 2)
absolute
magnitude
−3.26
1.62
A
B
C
D
p. 2
1.6 The distributions of spectral intensity I (in W m−2 per nm) of the Sun S and a star P are shown below. In
the H–R diagram shown, which one is the most probable star that P represents?
A.
B.
C.
D.
star W
star X
star Y
star Z
A
B
C
D
1.7 A star is orbiting another massive star with orbital speed 1500 km s−1. It is at position M now and is
moving clockwise as shown, what is the wavelengths of the red line (656 nm) of the hydrogen spectrum
observed from the Earth, when the star is at positions X and Y respectively?
A.
B.
C.
D.
656
656
653
653
X
nm
nm
nm
nm
Y
659 nm
653 nm
659 nm
656 nm
A
B
C
D
1.8 Which of the following observations about the stars near the edge of Milky Way leads to the proposal of
the existence of dark matter?
A. Their luminosity are lower than the expected ones.
B. Their luminosity are higher than the expected ones.
A
B
C
D
C. Their speeds around the galactic centre are lower than the expected ones.
D. Their speeds around the galactic centre are higher than the expected ones.
S6 Physics Mock Exam 2021-2022 (paper 2)
p. 3
Q.1: Structured questions
Other than the Sun, Sirus A is the brightest star in the sky observed on E arth. It has a mass of 2.1M  (M  =
mass of our Sun) and a radius of 1.7R  (R  = radius of our Sun). Its stellar parallax of 0.374''.
(a) Estimate the distance of Sirus A from the Earth in light years.
(2 marks)
(b) Apart from its distance from Earth, what do we have to measure about Sirus A, in order to estimate its
luminosity?
(1 mark)
(c) The luminosity of Sirus A is found to be 25.4 times that of the Sun.
(i)
Estimate the surface temperature of Sirus A. Hence, using the table shown, state the spectral class of Sirus A.
Take the surface temperature of the Sun to be 5800 K.
(3 marks)
spectral class
O
B
A
F
G
K
M
surface temperature
> 25 000 K
10000 – 25 000 K
7500 – 10 000 K
6000 – 7500 K
5000 – 6000 K
3500 – 5000 K
< 3500 K
(ii) Sketch the radiation curve for Sirus A in the graph beside. The radiation curve of our Sun is shown for
reference.
(2 marks)
(iii) Just like the Sun, Sirus A is also a main sequence star which emits light due to the nuclear fusion in its core.
According to scientists, although Sirus A initially has more nuclear fuel than our Sun, its nuclear fuel will be
used up in a shorter time.
Assume that:
(1) The initial amount of nuclear fuel is directly proportional to the mass of the star.
(2) The rate of nuclear fusion of a certain star does not change over time.
Estimate the total time for the nuclear fuel in Sirus A to be used up. Suppose the total time for Sun to use up its
nuclear fuel is 10 billion years.
(2 marks)
S6 Physics Mock Exam 2021-2022 (paper 2)
p. 4
Section B : Atomic World
Q.2: Multiple-choice questions
2.1
In Thomson’s ‘plum-pudding’ model of atoms, electrons are embedded in a cloud of positive charge. Which of the
following observations CANNOT be explained by this model?
(1) An atom is electrically neutral.
(2) In the -particle scattering experiment, most  particles nearly passed straight through the gold foil.
(3) In the -particle scattering experiment, a few  particles bounced back from the gold foil.
A. (2) only
B. (3) only
C. (2) and (3) only
A
B
C
D
D. (1), (2) and (3)
2.2 The threshold frequency that causes photoelectric effect on a certain metal surface is 1.0× 10 15 Hz. When
light of frequency 1.5× 10 15 Hz is illuminated on the metal surface, what will be maximum kinetic energy
of the photoelectrons?
A. 1.8 eV
B. 2.1 eV
C. 3.3 eV
D.
2.3
A
B
C
D
12.4 eV
The diagram below shows some energy levels of a hydrogen atom. A large number of hydrogen atoms in the
ground state are collided by electrons with kinetic energy of 12.8 eV. Which energy level will the electron in the
ground state be excited to ?
A.
n=5
B.
n=4
C.
n=3
D.
n=1
A
B
C
D
C
D
2.4 Some hydrogen atoms in the fourth excited state (i.e. n = 5) subsequently produces a spectrum
consisting of a series of discrete lines. How many spectral lines of different wavelengths are
there in the spectrum?
A. 25
B.
15
C.
10
D.
4
S6 Physics Mock Exam 2021-2022 (paper 2)
A
B
p. 5
2.5
The figure below shows part of the emission spectrum of hydrogen gas. All the spectral lines shown are produced
by electron transitions from higher energy levels to the first excited state
(n = 2). Which of the following statements is/are correct?
X
2.6
Y
(1)
Spectral line X has a higher frequency than spectral line Y.
(2)
The longest wavelength of these lines is about 660 nm.
(3)
The lines have the same frequencies as those of the dark lines in the absorption spectrum of hydrogen gas.
A.
(1) only
B.
(1) and (2) only
C.
(2) and (3) only
D.
(1), (2) and (3)
A
B
C
D
The de Broglie wavelength of a proton moving with kinetic energy E is . What is the de Broglie wavelength of an
 particle moving with the same kinetic energy? The mass of an  particle is about 4 times that of a proton.
A.
4
B.
2
C.
/4
D.
/2
A
B
C
D
2.7 The Hubble Telescope has an aperture diameter of 2.4 m. If it is used to take pictures on the Moon surface, which is
3.84 × 108 m away, estimate the minimum distance between two points on the Moon surface that can be resolved.
Take the wavelength of light to be 550 nm.
A. 107 m
B. 215 m
A
B
C
D
C. 1070 m
D. 2150 m
2.8 Which of the following statements concerning both the transmission electron microscope (TEM) and the scanning
tunnelling microscope (STM) are correct?
(1) Both TEM and STM make use of electrons to obtain images.
(2) Both TEM and STM can resolve details of a sample down to 1 nm.
(3) Both TEM and STM can only be used to observe conducting samples.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
A
B
C
D
D. (1), (2) and (3)
S6 Physics Mock Exam 2021-2022 (paper 2)
p. 6
Q.2: Structured questions
Light of wavelength 450 nm is incident on a metal surface. The power of the light reaching the metal surface is 5.0 W.
(a) (i) Find the frequency of the light.
(ii) Find the number of photons arriving at the metal surface per second.
(1 mark)
(2 marks)
(iii) If on average only one photoelctron is emitted for every two thousand photons absorbed by the metal surface,
calculate the resulting photoelectric current.
(2 marks)
(b) Light of different wavelength λ is allowed to illuminate the metal surface. The K.E.max against 1/ λ graph is
shown.
K.E. max / eV
1/  / × 10 6 m -1
(i) Explain how Einstein explained the increase in the maximum kinetic energy of electrons when the
(ii)
frequency of incident light increases.
(1 mark)
Estimate the Planck’s constant h.
(2 marks)
(c) Suppose the experiment is repeated with another piece of metal of larger work function.
(i) Explain the meaning of work function.
(ii)
(1 mark)
Sketch the above graph on the answer book. Use a dotted line to sketch the expected result when metal of
larger work function is used on the same graph.
S6 Physics Mock Exam 2021-2022 (paper 2)
(1 mark)
p. 7
Section C : Energy and Use of Energy
Q.3: Multiple-choice questions
3.1
Which of the following lamps has the highest end -use energy efficiency?
A.
B.
C.
D.
luminous flux
750 lm
900 lm
750 lm
600 lm
power rating
15 W
30 W
60 W
90 W
A
B
C
D
3.2 A light source S at a distance of 1 m from the wall is emitting light equally in all directions. The light ray is incident
normally at X and at an angle on Y. Find the illuminance at X : illuminance at Y.
wall
S
1m
X
m
Y
A. 4 : 1
B. 4 :
A
B
C
D
C. 2: 1
D: 2:
3.3 Referring to the above energy label of a storage type water heater, estimate the effective output power of
the heater when it is filled to maxi mum capacity with 40 L (1 L = 1000 cm 3 ) of water at 15℃.
(Given: specific heat capacity of water = 4200 J kg -1 ℃ -1 , density of water = 1000 kg m -3 )
A.
B.
C.
D.
1870 W
2430 W
85000 W
112000 W
S6 Physics Mock Exam 2021-2022 (paper 2)
A
B
C
D
p. 8
3.4 The battery of an electric vehicle has a capacity of 60 kW h. It is charged from empty to full for 10 hours at a
charging voltage of 220 V. Suppose 15% of energy is lost during the charging process, estimate the average charging
current.
A. 21 A
B. 24 A
A
B
C
D
C. 27 A
D. 32 A
3.5 A hybrid electric vehicle with a regenerative braking system is now decelerating, which of the following answers
matches with this situation?
A.
B.
C.
D.
A
3.6
B
C
D
The following graph shows the percentage of transmission of different electromagnetic radiations when passing
through three types of glass X, Y and Z.
percentage of
transmission
X
75%
50%
25%
0
% 300
Z
380
780
Y
2500
frequency / 10 12 Hz
Which of the following statements about these three types of glass is NOT correct? It is known that ultra-violet
radiation causes fabrics and wall coverings to fade in colour.
A.
X blocks the least amount of visible light.
B.
Y is the best in reducing the need of air conditioning.
A
B
C
D
C.
Z is the best in protecting fabrics and wall coverings from fading in colour.
D.
Sunlight passing through Z looks different in colour than
that passing through X and Y.
S6 Physics Mock Exam 2021-2022 (paper 2)
p. 9
3.7 A water pumping system is powered by a wind turbine with blade length 2.4 m. The system is used to pump water
up to a height of 5 m at a rate of m. The density of air is 1.3 kg m−3 and the wind speed is 5 m s−1. Find m if the
overall efficiency is 15%.
A
B
C
D
A. 7.4 kg s−1
B.
6.1 kg s−1
C. 5.2 kg s−1
D.
4.5 kg s−1
3.8 The following nuclear equation shows a typical fission reaction taking place in a nuclear power station.
Given: binding energy per nucleon of
binding energy per nucleon of
binding energy per nucleon of
(Hint: A
is 7.59 MeV.
is 8.27 MeV.
is 8.59 MeV.
atom has 235 nucleons)
Find the nuclear energy released in the process.
A. 9.27 MeV
B. 74.1 MeV
C. 180.3 MeV
D. 210.4 MeV
S6 Physics Mock Exam 2021-2022 (paper 2)
A
B
C
D
p. 10
Q.3: Structured question
A security station has the dimensions 2 m × 1.2 m × 1.2 m. There is a 0.8 m × 0.8 m single layer glass window
on EACH of the four vertical walls.
(a) (i) Find the OTTV of the security station.
(3 marks)
(Given: U-value of the wall: 15 W m−2 °C −1 ;
Average heat gain through EACH window due to conduction and radiation : 120 W )
(ii) The temperatures inside and outside of the station are 25 °C and 33 °C respectively. Find the rate
of heat transfer through the single glazed window by conduction.
(Given: U-value of a single glazed window: 5 W m −2 °C −1 )
(2 marks)
(iii) If a double-glazed window is used instead of a single-glazed one, how would the U-value of the
window change? Explain your answer.
(2 marks)
(b) To keep the security station cool, an air conditioner is installed. Given that the total rate of heat
transfer from outside into the room is 636 W. The heat generated by the guard inside the station is 64W.
(i) The COP of the air-conditioner is 2.0. Estimate the power consumed by the air conditioner.(2 marks)
(ii) A schematic diagram of the air conditioner is shown.
In which direction does the refrigerant flow through the expansion valve?
S6 Physics Mock Exam 2021-2022 (paper 2)
(1 mark)
p. 11
Section D : Medical Physics
Q.4: Multiple-choice questions
4.1 Jessica can see near objects clearly but cannot see things that are farther than 1.2 m from her eyes clearly. She wears
a pair of spectacles to correct her far point to infinity. What is the power of her spectacle lenses?
A.
B.
C.
D.
−0.833 D
+0.833 D
−3.17 D
+3.17 D
A
B
C
D
4.2 David is reading in his bedroom. When he takes a break, he looks out of the window and sees a bird flying in the sky.
Today is a sunny day, and his bedroom is dimmer than the outside. Which of the following statements is/are correct
when he starts looking at the bird?
(1)
(2)
(3)
The size of pupil of his eye decreases.
The ciliary muscle of his eye contracts.
The lens in his eye becomes thinner.
A.
B.
C.
D.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
A
B
C
D
4.3 A loudspeaker with power P is designed to produce sound at 0 dB, which normal people can barely hear. However,
Ken suffers from a hearing loss, and his threshold of hearing is 20 dB. Assume that the efficiency of converting
electrical energy to sound energy of the loudspeaker remains unchanged. What is the power required to produce
sounds that Ken can barely hear?
A.
B.
C.
D.
0.1P
10P
20P
100P
A
B
C
D
B
C
D
4.4 Which of the following statements about an endoscope is/are correct?
(1)
(2)
(3)
Fibre optic endoscopes can only produce black and white images.
Non-coherent fibre bundle is used to transmit images.
An optical fibre bundle with more and finer fibres forms images with a higher resolution.
A.
B.
C.
D.
(2) only
(3) only
(1) and (2) only
(2) and (3) only
A
4.5 Woody gets a head injury in a football match. He is sent to the hospital and the doctor performs an emergency
computed tomography (CT) scan for him. Which of the following could be a reason why the doctor performs a CT
scan instead of a conventional X-ray imaging?
(1)
(2)
(3)
CT scan provides good contrast between soft tissues structures.
CT scan can image the cross-section of a body and thus can locate the injury precisely.
CT scan does not make use of ionizing radiations to produce images.
A.
B.
C.
D.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
S6 Physics Mock Exam 2021-2022 (paper 2)
A
B
C
D
p. 12
4.6 The figure below shows the cross-section of a human body. A pair of X-rays source and detector is moved
horizontally to scan the body part.
Which of the following graphs best represents the variation of the intensity I of the X-rays detected?
A.
B.
C.
D.
A
B
C
D
4.7 Which of the following statements about radionuclide imaging (RNI) is INCORRECT?
A. Gamma camera is usually used to detect the radiation emitted from the patient’s body.
B. In RNI, a drug labelled with a radioactive isotope is injected to the patient’s body. A
C. RNI has good spatial resolution and can reveal the structures of organs clearly.
D. RNI can assess the functions of organs.
B
C
D
4.8 Gamma rays are frequently used in radiotherapy to treat cancer. In order to minimize the risk of damaging healthy
tissues, shields are used to control the exposure of the patients’ body to radiations. A gamma source produces a
equivalent dose rate of 16 μSv per hour at a certain point. If a 152 mm shield is applied, what will be the equivalent
dose rate at the same point? Given that the half-value thickness of the shielding material for gamma radiation is 46.5
mm.
A.
B.
C.
D.
0.609 μSv per hour
1.66 μSv per hour
4.89 μSv per hour
13.1 μSv per hour
S6 Physics Mock Exam 2021-2022 (paper 2)
A
B
C
D
p. 13
Q.4: Multiple-choice questions
(a) The figure below shows part of the middle ear. P is a structure connected to the outer ear and R is a structure
connected to the inner ear.
(i) Name P and R.
(2 marks)
(ii) Explain how the difference in the effective areas of P and R can help amplify the sound wave transmitted into the
inner ear.
(2 marks)
(b) The ultrasound transducer with coupling gel is now applied to a skin. There are several lay ers of tissues
underneath the skin, as shown in the figure below. The thickness of tissue X is 3.5 cm, and the thickness
of tissue Y is 6.0 cm. The ultrasound pulses reflected from the boundaries are displayed on a CRO as
shown on the right.
(i) State the function of the coupling gel.
(1 mark)
(ii) Find the ratio of the acoustic impedance of tissue X to that of tissue Y. Given that the density of tissue
X is 1060 kg m −3 and that of tissue Y is 1710 kg m −3 .
(3 marks)
(iii) Hence, estimate the percentage of ultrasound reflected at the boundary between X and Y.
(2 marks)
END OF PAPER
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