CCC HOH FUK TONG COLLEGE
Mock Examination 2011–2012
Physics Paper 2
Secondary：6
Date：01/03/ 2012
Time allowed：1 hour (11:15am – 12:15pm)
Marks：40
Name：____________________________
Number：_____
Class：S.6E
INSTRUCTIONS
(1)
Insert the information required in the space provided on Page 1.
(2)
Answer ALL questions.
(3)
Write your answers in the spaces provided in this Question-Answer Book. Do not write in
the margins. Answers written in the margins will not be marked.
(4)
Supplementary answer sheets will be provided on request. Insert the information required
and fill in the question number on each sheet.
(5)
The diagrams in this paper are NOT necessarily drawn to scale.
(6)
The last pages of this Question-Answer Book contain a list of data, formulae and
relationships which you may find useful.
1
Section B: Atomic World
Q.2: Multiple-choice questions
2.1
Which of the following statements about the photoelectric effect are incorrect?
(1)
The maximum kinetic energy of the emitted photoelectrons is given by K.E.max = hf
where f is the frequency of the incident radiation.
(2)
The photoelectric effect can be explained by the wave theory of light.
(3)
There is no time delay in the emission of photoelectrons when radiation of
sufficiently high frequency is applied.
(1) and (2) only
B
(2) and (3) only
C
(1) and (3) only
D
(1), (2) and (3)
A
B
C
D
The following figure shows some energy levels of an atom. Electron transitions P and Q
emit electromagnetic radiations of 650 nm and 2600 nm respectively.
Q
R
P
energy
What is the wavelength of the electromagnetic radiation emitted by transition R?
2.3
A
975 nm
B
1040 nm
C
1625 nm
D
1950 nm
A
B
C
D
Two point objects are placed close to each other. Both of them are illuminated by red
light. A man observes the two objects from a certain distance. Which of the following
methods can increase the resolving power of the man’s eyes?
(1)
Illuminate the objects with blue light instead of red light.
(2)
Replace the light source with a brighter one.
(3)
Move the objects slightly closer to the eyes.
2
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2.2
A
2.4
A
(1) only
B
(2) only
C
(1) and (3) only
D
(2) and (3) only
A
B
C
D
When an electron in a hydrogen atom drops from an excited state to the ground state, it
releases an energy of 10.2 eV. If the electron in that excited state completely escapes from
the atom after absorbing a photon, what is the minimum frequency of the photon?
2.6
8.21  1014 Hz
B
5.75  1015 Hz
C
5.13  1033 Hz
D
1.54  1034 Hz
A
B
C
D
Which of the following is NOT a physical property of carbon nanotubes?
A
high flexibility
B
high thermal conductivity
C
high strength
D
high electrical resistance
A
B
C
D
Which of the following statements about spectral lines of the hydrogen atom is/are
correct?
(1)
The line with the longest wavelength in the hydrogen emission spectrum is resulted
from the transition between the n =  level and the n = 1 level.
(2)
Each spectral line is resulted from an atomic transition in which only one photon is
emitted or absorbed.
(3)
Absorption spectrum is obtained when a sample of low pressure hydrogen gas is
bombarded by a beam of energetic electrons.
A
(1) only
B
(2) only
C
(1) and (3) only
D
(2) and (3) only
A
B
C
D
3
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2.5
A
2.7
In a transmission electron microscope, electrons are accelerated in an electron gun by a
voltage of 50 kV. Estimate the wavelength of the accelerated electrons.
8  104 nm
B
0.005 nm
C
0.2 nm
D
3 nm
A
B
C
D
Daisy observes two point objects which are very close to each other with a microscope.
The following figures show the intensity of the diffraction patterns of the objects under
different settings. In which situation are the two objects not resolved?
A
intensity
A
B
intensity
C
intensity
D
intensity
B
C
Answers written in the margins will not be marked.
2.8
A
D
4
Q.2: Structured question
The set-up shown in Figure (a) is used to study the relationship between the stopping
potential Vs of metal X and the frequency f of incident light. A photoelectric unit is
connected to a power supply and a galvanometer. A beam of monochromatic light is
directed onto metal X in the photoelectric unit. The voltage of the power supply is
increased gradually. It reaches the stopping potential when the reading of the
galvanometer becomes zero.
incident light
metal X
Figure (a)
photoelectric unit
P
Q
By directing different frequencies of monochromatic light onto metal X, a set of stopping
potentials are obtained. The results are plotted on the graph in Figure (b).
stopping potential Vs / V
1.5
Figure (b)
1.0
0.5
0
1
2
3
4
5
6
frequency f /
 1014 Hz
–0.5
–1.0
–1.5
–2.0
5
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electrode
(a)
Which terminal of the power supply, P or Q, should be set at a higher potential?
(1 mark)
From the graph in Figure (b), estimate the Planck constant (in J s) and the work
function of metal X (in eV).
(c)
(5 marks)
Hence, calculate the maximum kinetic energy of an electron emitted by metal X
when the frequency of the monochromatic light is 7  1014 Hz. Express your
answer in eV.
(d)
(2 marks)
Metal Y with work function 1.2 eV is used to replace X. In Figure (b), sketch the
graph for metal Y.
(2 marks)
6
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(b)
Section C: Energy and Use of Energy
Q.3: Multiple-choice questions
3.1
A point light source Q is 1 m away from the wall as shown.
S
Q
A
wall
Answers written in the margins will not be marked.
1m
T
Which of the following ways can halve the illuminance on A?
3.2
(1)
Halve the luminous flux produced by the point light source.
(2)
Move Q to a position 1 m from the original position on the line ST.
(3)
Reduce the distance between Q and the wall to 0.5 m.
A
(1) only
B
(2) only
C
(1) and (3) only
D
(2) and (3) only
A
B
C
D
What can we do to save energy?
(1)
Use light emitting diodes instead of incandescent lamps.
(2)
Buy electric appliances rated as grade 5 in the Hong Kong Energy Efficiency
Labelling Scheme.
3.3
(3)
Travel by MTR instead of private cars.
A
(1) only
B
(2) only
C
(1) and (3) only
D
(1), (2) and (3)
A
B
C
D
Which of the following statements about an air-conditioner is/are correct?
(1)
Its cooling capacity can be measured in kW.
(2)
Its cooling capacity can be higher than its input power.
(3)
It transfers heat against the natural direction of flow.
7
3.4
A
(1) only
B
(2) only
C
(1) and (3) only
D
(1), (2) and (3)
A
B
C
D
A window wall is of dimension as shown. The temperatures inside and outside the
window are 25 oC and 30 oC. If heat is transferring through the wall at a rate of 330 J s -1,
calculate the U-value of the wall.
5 mm
2.6 m
3.5
A
2.12 W m-2 K-1
B
2.54 W m-2 K-1
C
10.0 W m-2 K-1
D
12.7 W m-2 K-1
A
B
C
D
An artificial satellite orbits around the earth near the outer surface of the earth’s
atmosphere. On the satellite, there is a solar panel of area 20 m2. The efficiency of the
solar panel is 15%. What is the power output of the solar panel when its normal makes an
angle of 30 to the incident sunlight? Take the solar constant to be 1366 W m2.
normal
sunlight
30
solar panel
A
2050 W
B
3550 W
C
4100 W
D
27300 W
A
B
C
D
8
Answers written in the margins will not be marked.
2m
3.7
3.8
Which of the following statements about a hybrid vehicle is/are correct?
(1)
It contains an internal combustion engine.
(2)
It contains a regenerative braking system.
(3)
It releases less greenhouse gases than a petrol vehicle.
A
(1) only
B
(3) only
C
(1) and (3) only
D
(1), (2) and (3)
A
B
C
D
Which of the following measures can help a building attain high energy efficiency?
(1)
Construct the building envelope with high OTTV.
(2)
Install solar control window films.
(3)
Reuse the heat generated by central air-conditioning system.
A
(1) and (2) only
B
(1) and (3) only
C
(2) and (3) only
D
(1), (2) and (3)
A
B
C
D
When a nuclear power plant experiences an emergency, the reactor is shut down
automatically by inserting the control rods entirely into the core. The function of the
control rod is
A
to absorb the uranium atoms in the fuel rods.
B
C
to absorb the energy released in the fission process. A
to absorb the fast moving neutrons.
D
to slow down the fast moving neutrons.
B
C
D
9
Answers written in the margins will not be marked.
3.6
Q.3: Structured question
A company has installed a wind turbine on the top of the building to generate electricity.
The length of the blade is 0.7 m and the air density is 1.25 kg m-3.
Estimate the maximum power output of the wind turbine if the wind speed is
15 m s-1.
(b)
(c)
(2 marks)
The actual power generated by the turbine is 1200 W. Suggest TWO reasons why
the actual power generated is much smaller than that in (a).
(2 marks)
Routine maintenance is necessary to keep the efficiency of the turbine.
Point out
TWO major steps.
(2 marks)
10
Answers written in the margins will not be marked.
(a)
(d)
Some suggests using solar panels to generate electricity instead of wind turbines.
Give TWO advantages and TWO disadvantages of using solar panel over using
(e)
(2 marks)
The power output may be more than enough in certain situations.
(i)
Give a reason.
(1 mark)
(ii)
Suggest a practical method to save the excess power.
(1 mark)
END OF PAPER
11
Answers written in the margins will not be marked.
wind turbines.
List of data, formulae and relationships
Data
R = 8.31 J mol1 K1
NA = 6.02  1023 mol1
g = 9.81 m s2 (close to the Earth)
G = 6.67  1011 N m2 kg2
c = 3.00  108 m s1
e = 1.60  1019 C
me = 9.11  1031 kg
0 = 8.85  1012 C2 N1 m2
0 = 4  107 H m1
u = 1.661  1027 kg (1 u is equivalent to 931 MeV)
AU = 1.50  1011 m
ly = 9.46  1015 m
pc = 3.09  1016 m = 3.26 ly = 206 265 AU
 = 5.67  108 W m2 K4
h = 6.63  1034 J s
molar gas constant
Avogadro constant
acceleration due to gravity
universal gravitational constant
speed of light in vacuum
charge of electron
electron rest mass
permittivity of free space
permeability of free space
atomic mass unit
astronomical unit
light year
parsec
Stefan constant
Planck constant
Rectilinear motion
Mathematics
For uniformly accelerated motion:
Equation of a straight line
y = mx + c
Arc length
= r
Surface area of cylinder
= 2rh + 2r2
Volume of cylinder
= r2h
Surface area of sphere
= 4r2
Volume of sphere
4
= πr 3
3
v
=
s
=
v2 =
u + at
1
ut + at 2
2
u2 + 2as
For small angles, sin   tan    (in radians)
Astronomy and Space Science
Energy and Use of Energy
GMm
r
P = AT4
f v λ
 
f0 c λ0
A(TH  TC )
Q
=k
d
t
k
U=
d
1
P = Av 3
2
U =
gravitational potential energy
Stefan’s law
Doppler effect
Atomic World
Medical Physics
1
m0 v max 2 = hf   Einstein’s photoelectric equation
2
4
1  m e 
13 .6
En =  2  e 2  =  2 eV
2
n  8h  0 
n
energy level equation for hydrogen
atom
h
h
= =
de Broglie formula
p mv
=

1.22 λ
d
Rayleigh criterion (resolving power)
1.22 λ
d
1
power =
f
L = 10 log
rate of energy transfer by conduction
thermal transmittance U-value
maximum power by wind turbine
Rayleigh criterion (resolving power)
power of a lens
I
I0
intensity level (dB)
Z = c
acoustic impedance
2
I
(Z  Z1 )
= r = 2
intensity reflection coefficient
I 0 (Z 2  Z1 ) 2
I = I0ex
transmitted intensity through a
medium
12
A1.
E = mcT
energy transfer during
heating and cooling
D1.
F=
A2.
E = lm
energy transfer during
change of state
D2.
E=
A3.
pV = nRT
equation of state for an
ideal gas
D3.
A4.
pV =
1
Nmc 2
3
kinetic theory equation
A5.
EK =
3RT
2N A
molecular kinetic energy
v  p
=
t  t
Q1Q 2
4 π 0 r 2
Q
Coulomb’s law
4π 0 r 2
electric field strength due to a
point charge
V=
Q
4π 0 r
electric potential due to a
point charge
D4.
E=
V
d
electric field between parallel
plates (numerically)
D5.
I = nAvQ
general current flow equation
D6.
R=
force
D7.
R = R1 + R2
l
resistance and resistivity
A
B1.
F =m
B2.
moment = F  d
moment of a force
D8.
B3.
EP = mgh
gravitational potential
energy
D9.
P = IV = I2R
power in a circuit
B4.
EK =
kinetic energy
D10.
F = BQv sin 
force on a moving charge in a
magnetic field
B5.
P = Fv =
mechanical power
D11.
F = BIl sin 
force on a current-carrying
conductor in a magnetic field
B6.
a=
centripetal acceleration
D12.
V=
B7.
F=
Newton’s law of
gravitation
D13.
B=
D14.
B=
fringe width in
double-slit interference
D15.
=N
D16.
Vs N s

Vp N p
ratio of secondary voltage to
primary voltage in a
transformer
E1.
N = N0ekt
law of radioactive decay
E2.
t1 =
1
mv 2
2
W
t
v2
= 2r
r
Gm1 m 2
r
2
λD
a
C1.
y =
C2.
d sin  = n
diffraction grating
equation
C3.
1 1 1
 =
u v f
equation for a single
lens
1
1
1
=
+
R R1 R 2
2
BI
nQt
0 I
2 πr
 0 NI
l

t
ln 2
k
resistors in series
resistors in parallel
Hall voltage
magnetic field due to a long
straight wire
magnetic field inside a long
solenoid
induced e.m.f.
half-life and decay constant
E3.
A = kN
activity and the number of
undecayed nuclei
E4.
E = mc2
mass-energy relationship
13