Unformatted text preview: PP-DSE
PHY PAPER 2 HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITY HONG KONG DIPLOMA OF SECONDARY EDUCATEON EXAMINATION .
\ Candidate Number PRACTICE PAPER
PHYSICS PAPER 2 Question-Answer Book (1 hour)
This paper must be answered in English INSTRUCTIONS I (1) (5) ©Z§t%%§it)§2§5t?2% After the announcement of the start of the
examination, you shoutd first write your Candidate
Number in the space provided on Page 1 and stick
barcode labels in the spaces provided on Pages 1,
3, 5, 7, 9 and 11. This paper consists of FOUR sections, Sections A,
B, C and D. Each section contains eight multiple-
choice questions and one structured question which
carries 10 marks. Attempt ALL questions in any
TWO sections. Write your answers in the spaces provided in this
Question—Answer Book. Do not write in the margins.
Answers written in the margins wilt not be marked.
For multiple-choice questions, blacken the
appropriate circle with an HB pencil. You should
mark only ONE answer for each question. If you
rnark more than one answer, you will receive NO
MARKS for that question. Graph paper and supplementary answer sheets wit!
be provided on request. Write your candidate
number, mark the question number box and stick a
barcode tabel on each sheet, and fasten them with
string INSIDE this Question—Answer Book. The diagrams in this paper are NOT necessarily
drawn to scale. The East pages of this Question-Answer Book
contain a list of data, formulae and relationships
which you may find useful. No extra time will be given to candidates for sticking on the barcode labels or fitting in the question
number boxes after the ‘Time is up' announcement. fiéfilfii’tfi Hong Kong Examinations and Assessment Authority
All Rights Reserved 2012 PP-DSE-PHY 2—1 1 Please stick the barcode label here. III III Illlllllllllllllllllllll lllll *A150E002* Section A : Astronomy and Space Science Q.l: Multiple-choice questions 1.1 The figure below shows the view facing the south horizon in Hong Kong. are l are 2 looking south The two arcs represent the tracks of stars. Which of the following statements is/are incorrect?
The stars move clockwise along the arcs. The stars move anticlockwise along the arcs. The time taken for a star to follow path are l is longer than that of path are 2. (l)
(2)
(3) (1) only A
(2) only (1) and (3) only 0
(2) and (3) only B C D
O O O In 1838, German astronomer Bessel announced that the parallax of 61 Cygni is 0.314 arcseconds. What is the distance of 61 Cygni from Earth according to Bessel’s measurement ? A. 0.981y
B. 1.02 ly
c. 3.181y
D. 10.381y ABCD
0000 Answers written in the margins will not be marked. 1.3 Which of the following statements about retrograde motion of planets is correct ? A. Retrograde motion can only be observed at locations near the equator. B. Only planets closer to the Sun than the Earth exhibit retrograde motion. C During retrograde motion, an observer on Earth sees the planet move from east to west
over the course of several weeks or months.
The geocentric model cannot explain the retrograde motion of planets. A BCD
0000 Answers written in the margins will not be marked. PP-DSE-PHY 2—2 2 Answers written in the margins will not be marked. Answers written in the margins will not be marked. Please stick the barcode label here. If the acceleration due to gravity on the Moon’s surface is 1f6 of that on the Earth’s surface, what is the
gravitational potential energy with respect to the surface of the Moon for an object of mass m which is I m above the Moon’s surface ‘? Given : R = radius ofthe Moon (>> 1 m)
M: mass of the Moon
G = the universal gravitational constant
g = acceleration due to gravity (close to the Earth) —mg/6
rag/6
—GMm/R
GMm/R ABCD
0000 A satellite of mass m is in a circular orbit of radius r around a planet of mass M and radius R. What is the
extra kinetic energy required by the satellite to escape the gravitational attraction of the planet ? Given 1 G = the universal gravitational constant A. GMm
2r
GMm r
GMm 2R
GMm
R ABCD
0000 American astronomer Hubble discovered that the recession velocities v of galaxies are proportional to their
distances at from the Earth, v = Hd, where H is the Hubble constant. Which ofthe following is not a unit of
the Hubble constant '3 Answers written in the margins will not be marked. PP—DSE—PHY 2-3 km s"l Mpc"
m s"I 1y S S—l A B c D
O O O O Go on to the next page Answers written in the margins will not be marked. (For questions 1.7 and 1.8) The figure below shows the radiation curves of four stars. ultraviolet Intensity ole
Wavelength / x 10'6 m Which star has the highest surface temperature ‘2 star A A B C D
star B
star C O O O 0
star D Which of the following statements about the stars are correct '? (I) The area under the curve is proportional to the surface temperature of that star.
(2) The colours of the four stars are different.
(3) If stars C and D have the same luminosity, star D has a larger radius. A. (1) and (2) only A B C D
B. (1) and (3) only c. (2) and (3) only 0 O O O
D. (1), (2) and (3) Answers written in the margins will not be marked.
Answers written in the margins will not be marked. Answers written in the margins will not be marked. PP-D SE—PHY 24 4 Answers written in the margins will not be marked. Q.1: Structured question (a) We observe a galaxy X as shown in Figure 1.1. X has negligible velocity relative to the Earth.
Points A and B are both 10 kpe from the centre. The wavelengths of the H-alpha lines from the
hydrogen gas at points A and B are 656.83 nm and 655.73 nm respectively. The wavelength of the
i—I—alpha line measured in the laboratory is 656.28 mm. 4‘— lOkpc H‘— 10kpc _* edge-on view of galaxy X Figure 1.1 Determine the speed of the hydrogen gas at point A along the line of sight of an observer on Briefly expiain at which point, A or B, the hydrogen gas is moving towards the Earth.
(2 marks) Assuming that the hydrogen gas at points A and B are moving in a circular path around the
centre ofX, and that the mass of X is concentrated at its centre, estimate the mass of X. Answers written in the margins will not be marked. Answers written in the margins will not be marked. PP—DSE-PHY 2A6 Please stick the barcode label here. Observations were made on another galaxy Y, as shown in Figure 1.2. edge-on view of galaxy Y Figure 1.2 The angular separation between points C and E is L6". Given that Y is 950 kpc from the Earth, express the separation between C and E in kpc.
(2 marks) arked. Further observations show that the velocities of hydrogen gas at points D and E along the line
of sight of an observer on the Earth are about the same. What could be inferred about the
mass distribution of Y ? Assume that the hydrogen gas at points D and E are moving in
circular paths around the centre of Y. ers written in the margins will not be m Answers written in the margins will not be marked. Answ Answers written in the margins will not be marked. PP-DSE—PHY 2—7 7 Go on to the next page Section B : Atomic World
Q.2: Multiple-choice questions 2.1 Which of the following can be concluded from the Rutherford scattering experiment ? (1) The nucleus of an atom consists of protons and neutrons. (2) The nucleus of an atom is very small compared to the size of the atom. (3) Electromagnetic waves emitted from atoms of gases are of specific frequencies.
A. (2) only A B C D
B. (3) only 0 O O O C. (1) and (2) only
D. (1)and (3) only The ionization energy for a hydrogen atom in ground state is 13.6 eV. A photon of energy 4.53 eV strikes a
hydrogen atom in ground state. The hydrogen atom will A. not be excited to a higher energy level. A B C D
B. be excited to the first excited state.
C. be excited to the third excited state. O O O D. be ionized. 2.3 The wavelength of the radiation emitted when an electron of an atom drops from the j‘“ excited state of
energy E,- to a lower kth excited state of energy Ek is ABCD
0000 Answers written in the margins will not be marked.
Answers written in the margins will not be marked. 2.4 The de Broglie wavelength of a particle at speed 1: is 2.. If the speed of the particle is doubled, the
de Broglie wavelength is A. $14 A B C D
B. 21/2
C. A O o o o
D. 21 Answers written in the margins will not be marked. PP-DSE-PHY 2—8 8 Answers written in the margins will not be marked. 2.5 A beam of electrons is incident on a thin film of crystal.
fluorescent screen. Please stick the barcode label here. A pattern of bright and dark rings is observed on a Which physical phenomenon explains the formation of the pattern '? electron beam 1 0 crystal Photoelectric effect
Electron diffraction
Ionization of atoms
Lotus effect Which of the following statements about different microscopes is/are correct? (1) The resolution of an optical microscope will increase if red light instead of blue light is used to illuminate the specimen. (2) A transmission electron microscope (TEM) uses magnetic field to focus the electron beam.
(3) Only specimens that conduct electricity can be studied by a scanning tunnelling microscope (STM). A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only Estimate the wavelength of electrons when they are accelerated in a transmission electron microscope (TEM) with a voltage of 76 kV. A. 2.4x 1042111
B. 4.5 x10“‘2m
C. 1.4x10’10m
D, 9.6x10’9m screen ABCD
OOOO ABCD
0000 Answers written in the margins will not be marked. ABCD
0000 Which of the following are possible means by which nano particles could get into the human body? ( l) The skin having direct contact with nano particles.
(2) Inhalng nano particles into the lungs while breathing. (3) Ingesting food containing nano particles. A. (1) and (2) only
B. (1)and (3) only
C. (2) and (3) only
D. (l), (2) and (3) Answers written in the margins will not be marked. PP-DSE-PHY 2—9 9 ABCD
0000 Go on to the next page Q.2: Structured question (a) In studying the photoelectrons emitted from sodium, it was found that no photoelectrons were
emitted when the wavelength ofthe incident light was longer than 5.27 x 10’7 m. (i) Explain why the wave model of light cannot account for this phenomenon.
(2 marks) (ii) Determine the work function for sodium. Express your answer in electron-volts.
(3 marks) (iii) What is the physical meaning of work function ? Answers written in the margins will not be marked. Answers written in the margins will not be marked. Answers written in the margins will not be marked. PP-Dsa—PHY 2—1 0 10 Answers written in the margins will not be marked. Please stick the barcode label here. Figure 2.1 shows a photoelectric smoke detector Peter made for a science project competition. It
consists of a light source S, a photocell C and an alarm circuit. When smoke enters the detector, light from S is scattered by the smoke particles and enters C as shown in Figure 2.2.
Photoelectrons are produced in C when light is‘incident on its sodium surface. The alarm is triggered when the photoelectric current is larger than 1 x 10'8 A. scattered
light beam Figure 2.1
(i) If 5% of the photons incident on the sodium surface of C emit photoelectrons, what is the
minimum number of photons incident on the sodium surface of C in 1 s when the alarm is
triggered ?
(2 marks) (ii) Peter claimed that the detector will become more Sensitive if a light source of the same type as S
but of higher intensity is used. Comment on his suggestion. (2 marks) Answers written in the margins will not be marked. 11 PP-DSE-PHY 2-11 Go on to the next page Answers written in the margins will not be marked. Section C : Energy and Use of Energy Q3: Multiple—choice questions 3.1 A 100 W filament light bulb and a 22 W compact fluorescent lamp both produce a luminous flux of
1600 lm. Which of the following statements‘about the two light sources is/are correct ?
(1) Both light sources give out the same amount of energy in the form of electromagnetic waves in
l s.
(2) 78 J of electrical energy is converted to heat in the filament light bulb in l s.
(3) Both light sources have the same brightness to the human eye when observed from the same
distance.
A. (1) only A B C D
B. (3) only
C. (1) and (2) only 0 O O O
D. (2) and (3) only
3.2 A point light source with luminous flux F is illuminating a point P on a table surface as shown in the figure
below. The illuminance at point P is
Q point light source
A F cos 6’
' 4m"2
F cos2 6
B. —-2—
41w
F cos l90° — 9)
C- a
47W"
F cos2 90° — 9
D. 2
4???
3.3 Which of the following statements about an electric hotplate and an induction cooker is/are correct?
(1) Both cookers make use of the heating effect of a current.
(2) Only metal cooking pots can be used for both cookers.
(3) In general, an induction cooker has a higher energy efficiency than an electric hotplate.
A. (1) only A B C D
B. (2) only
C. (l) and (3) only 0 O O O
D. (2) and (3) only Answers written in the margins will not be marked. 12 PP-DSE—PHY 2—12 Answers Written in the margins will not be marked. Answers written in the margins will not be marked. 3.4 The table below shows the data of a house. Calculate the Overall Thermal Transfer Value of the house. Rate of heat transfer I W
Total area / m2 A. 30 w nr2 B. 127 w m’2
c. 310 w er2
D. 381 w m—2 ABCD
0000 A wind turbine has an overall efficiency of 30% and its output power is 360 kW when the wind blows
normally at the turbine with a constant velocity of 10 rn s'l. Find the length of the blades of the wind
turbine. Given: density of air = l.2 kg In—3 A. 4.1 m
B. 7.6 m
C. 13.8 m
D. 25.2 m ABC-D
0000 The difference in mass between a uranium-238 nucleus and its constituent nucleons is 1.88482 u.
Determine the binding energy per nucleon of a uranium-238 nucleus. A. 2.08 MeV B. 7.37 MeV C. 448.59 MeV
D. 1754.77 MeV A B C D
O O O Q
Which ofthe following is the function ofthe control rods in a fission reactor 7 They slow down neutrons. They absorb neutrons. They absorb heat from the reactor.
They transfer heat to the generator. ABCD
0000 Estimate the electrical power output of a 20 m2 solar panel when it is illuminated with sunlight of intensity
1 kW rrf2 at an angle of 30° to the vertical. sunlight Given: efficiency ofthe solar panel = 12% A. 1200 W
B. 1386 W
C. 2073 W
D. 2400 W ABCD
OOOO Answers written in the margins will not be marked. 13 PP-DSE—PHY 2713 Go on to the next page Answers written in the margins will not be marked. Answers written in the margins will not be marked. Q.3: Structured question (a) The heat transfer through a window can be reduced by using double—glazed glass. The table below
shows some information of two types of windows, both made from the same type of glass. Single layer Double—glazed 0.03 m (0.01 m for each layer) 5.7 W m'2 K—1 2.8 w m-2 K"1 Thickness Thermal transmittance U-value Suggest two reasons why the thermal transmittance of the double—glazed window is smaller
than that or" the single layer window. (2 marks) On a hot sunny afternoon, the temperatures outside and inside a room are 36°C and 24°C
respectively. If the double-glazed window is used in the room and the area of the window is 2 m2,
estimate the rate of heat transfer due to conduction through this window. (1) (1 mark) Answers written in the margins will not be marked. (2) Briefly explain whether the actual rate of heat transfer will be higher or lower than
your answer in part (1). (2 marks) Answers written in the margins will not be marked. 14 PP—DSE-PHY 2-14 Answers written in the margins will not be marked. (a) (b)
(i) (ii) (iii) Other than using double—glazed windows, suggest one method to reduce the heat flow through windows.
( 1 mark) An air—conditioner is installed in a room to keep the room cool. Briefly explain how the refrigerant in an air~conditioner absorbs heat from the room.
(2 marks) The energy label of the air-conditioner is shown in Figure 3.1. firmer mgr-"g 'fi'éiiififi; Annual energy consumption (kWh)(cooling)
Based on 1200 hrsfyr operation = 1106 Cooling capacity (kW) = 2.54 Answers written in the margins will not be marked. males Q msn Figure 3.] Estimate the amount of heat that can be removed from the room by the air—conditioner in 5 minutes.
(2 marks) Answers written in the margins will not be marked. PP—DSE-PHY 2-15 Go on to the next page 15 Section D : Medical Physics QA: Multiple-choice questions 4.1 The far point of Phoebe’s eye is at 60 cm and its lens-to—retina distance is 2.5 cm. What is the power of
the corrective lens that she should wear ? A. — 2.0 D A B C D
B. — 1.7 D C. 1.7 D O O O O
D. 2.0 D 4.2 Which of the following features of the middle ear amplify the pressure ? (l) The middle ear is filled with air.
(2) The ear bones form a lever system.
(3) The area of the ear drum is larger than that of the oval window. A (1) and (2) only A B C D
B. (l) and (3) only c. (2) and (3) only 0 O O O
D (1), (2) and (3) The sound intensity of a machine is 0.01 W m’z. By adding a noise barrier, the sound intensity is reduced to 6 x 10'6 W m’z. Find the reduction in the sound intensity level.
Given : threshold of hearing I I x 10' '2 W m"2 In“
Lu A. 32dB A B C D
B. 68dB
c. 88dB 0 O O O
D. 100dB (For questions 4.4 and 4.5) The following table shows the acoustic impedances and the densities of three
different mediaX, Y and Z. Answers written in the margins will not be marked. Acoustic impedance / x 106 Ray] Density / k m“6 1.48 1000
1058
1060 Answers written in the margins will not be marked. 4.4 Arrange the speed of sound in the three media, vX, W and v2, in descending order.
A. VX > V)’ > V2 A B C D
B. V12 > VX > V2
C. VZ > VX> Vy O O O O
D. VZ > V}! > PX 4.5 What is the intensity reflection coefficient between medium X and medium Z for normal incidence ?
A. 7.97 x 10" A B C D
B. 8.48 x 10’4
c. 3.29 x 10’3 O O O O
D. 5.73 x 10'2 Answers written in the margins will not be marked. PP-DSE-PHY 2—1 6 16 Answers written in the margins will not be marked. 4.6 Which of the following statements about a fibre optic endoscope is incorrect? Coherent bundle fibres are used for image transport. The cladding of the optical fibre must have a smaller refractive in
inside. The critical angle of the optical fibre should be as large as possible. A.
B.
C A B
O O 4.7 (1) (2) radiographic imaging. (3) Tracers are used to absorb radiation.
A.
B.
C.
D. (1) only
(2) only
(1) and (3) only
(2) and (3) only A B
O O 4.8 Technetium-99m has a half~life of 6 hours, and a biological half—life of 3 hours. injection of technetium-99m at 12:00 noon. (1) the initial value. Tissue samples can be obtained at the same time for further examination. dex than the glass fibre c D
O Q Which of the following statements about radionuclide planar imaging is/are incorrect ? RadiOnuclide planar images provide functional information about the organ.
Radiation of radionuclide planar imaging stays shorter inside our body than that of X-ray c D
O O A patient is given an Which of the following statements is/are correct? At 3:00 pm, the number of undecayed technetium nuclei in the patient’s body is less than half of (2) All the technetium nuclei will be removed from the body by biological processes by 6:00 pm.
(3) All the technetium nuclei removed from the body by biological processes are decayed.
A. (1) only A B C D
B. (2) only
C. (1) and (3) only 0 O O O
D. (2) and (3) only Answers written in the margins will not be marked. PP-DSE-PHY 2—17 17 Go on to the next page Answers written in the margins will not be marked. Answers written in the margins will not be marked. Q.4: Structured question The table below shows the linear attenuation coefficient, ,u, of X-rays for different tissues. Linear attenuation
coefficient/cm"i Suggest one reason to explain why the linear attenuation coefficient of the lung is smaller than that
of the liver. Show that the half—value thickness = 11% . The intensity of a beam of X-ray drops to 1/8 of its initial value after passing through a lung.
Estimate the thickness of the lung. Answers written in the margins wili not be marked. 18 PP-DSE-PHY 2-18 Answers written in the margins will not be marked. Answers written in the margins will not be marked. (‘...
View
Full Document
