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07 AL Physics/M.C./P.1
2007 Hong Kong Advanced Level Examination
AL Physics
Multiple Choice Questions
1.
3.
P
Q
W
The figure shows a weight W supported by
two light rigid rods P and Q. The rods are
smoothly hinged to the wall and mounted in
the same vertical plane. Which of the
following descriptions about the rods is
correct?
A.
B.
C.
D.
rod P
in compression
in compression
in tension
in tension
rod Q
in tension
in compression
in tension
in compression
An object is projected vertically upwards
from the ground. If air resistance is taken
into account, which of the following graphs
best shows the variation of the velocity v of
the object with time t, starting from the
moment when the object leaves the ground (t
= 0) up to the time when it returns to the
ground (t = T)?
A.
B.
2.
constant
velocity
m

C.
M
A wedge of mass M is fixed to the ground.
A block of mass m slides down the wedge
with constant velocity as shown. What is
the normal reaction exerted by the ground on
the wedge?
A.
B.
C.
D.
(M + m)g
Mg + mg cos 
Mg + mg cos2
Mg + mg cos  sin 
D.
07 AL Physics/M.C./P.2
4.
An aircraft flies with a constant speed in a
horizontal circle of radius 10 km. If its
wings slant at an angle of 21.8 to the
horizontal, find the speed of the aircraft.
7.
Which of the following statements about
simple harmonic motion in one dimension
is/are INCORRECT?
(1) The amplitude of oscillation must be
small.
(2) The acceleration is always directed
towards a fixed point.
(3) The frequency of oscillation is
independent of the amplitude.
A.
B.
C.
D.
5.
280 ms-1
200 ms-1
140 ms-1
100 ms-1
A.
B.
C.
D.
In which of the following situations does the
person
concerned
experience
‘weightlessness’?
8.
(1) an astronaut in a spacecraft which is
coasting in outer space with its rocket
engines shut off
(2) an astronaut in a spacecraft which is
decelerating to make a soft landing on
the moon
(3) a parachutist descending with a constant
velocity in the air
(1) only
(3) only
(1) and (2) only
(2) and (3) only
O
X
Q
A particle performs simple harmonic motion
along a straight line between P and Q as
shown. The particle passes the equilibrium
position O and travels to the right at time t =
0. It passes point X the first time after 3 s
and it passes X the second time after a
further 2 s. After what further time will the
particle pass X the third time?
A.
B.
C.
D.
16 s
14 s
12 s
10 s
ultra-violet radiation
10-8 m
10-8 m
10-10 m
10-10 m
microwaves
10-2 m
10-5 m
10-2 m
10-5 m
A diver at a depth of x below the water
surface looks up and finds that the sky
appears to be within a circle of radius r. The
critical angle of water in this case is given
by
A.
B.
C.
D.
6.
P
Which of the following best gives the orders
of magnitude of the wavelengths of ultraviolet radiation and microwaves in air?
A.
B.
C.
D.
9.
A.
B.
C.
D.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
tan-1 (r/x).
sin-1 (r/x).
tan-1 (x/r).
sin-1 (x/r).
10.
A beam of monochromatic light falls at
normal incidence on a diffraction grating.
Third-order diffracted beams are found at
angles of 45 to the incident direction. What
07 AL Physics/M.C./P.3
is the highest order of diffracted beam that
can be observed?
A.
B.
C.
D.
(3) The mass of P is greater than that of Q.
A.
B.
C.
D.
3rd order
4th order
5 th order
6 th order
(1) only
(3) only
(1) and (2) only
(2) and (3) only
14.
11. In a Young’s double-slit experiment using
monochromatic light of wavelength 550 nm,
the fringes are observed through the
eyepiece of a travelling microscope at a
distance of 1.0 m from the double slits.
If .the separation between the first and the
fifth dark fringes is 5.0 mm, find the slit
separation.
A.
B.
C.
D.
X
72
0.3  10-4 m
1.1  10-4 m
4.4  10-4 m
5.5  10-4 m
+Q
0.5
1.0
2.0
infinite
A.
B.
C.
D.
13. The figure shows two small charged spheres
P and Q suspended by identical nylon
threads from a fixed point O. At equilibrium,
the threads OP and OQ make angles  and 
( < ) with the vertical.
O

40
The above figure gives the electric field
strength (in arbitrary units) at various points
near an isolated point charge +Q. Which of
the following correctly gives the electric
field strength (in the same arbitrary units) at
X and at Y?
12. An object is placed at the focus of a concave
lens of focal length 10 cm. What is the
magnification of the image formed?
A.
B.
C.
D.
360
Y
electric field
strength at X
72
72
90
90
electric field
strength at Y
30
36
30
36
15.

Q
P
Which of the following conclusions must be
correct?
(1) Both P and Q carry positive charges.
(2) The charge on P is greater than that on
Q in magnitude.
In the above figure, XYZ is a small rightangled triangular metal frame moving with a
constant velocity across a rectangular region
PQRS with a uniform magnetic field
pointing into the paper. Which of the
following graphs best shows the variation of
the current I induced in the frame with time t?
07 AL Physics/M.C./P.4
A.
I
0
t
B.
I
0
t
C.
I
0
t
D.
I
0
t
16.
The above figure shows the V-I
characteristic curves of resistance wire X
and filament bulb Y. If they are connected
in series with a 12 V d.c. supply of
negligible internal resistance, estimate the
voltage across the bulb Y.
07 AL Physics/M.C./P.5
A. 3V
B. 4V
C. 5V
D. 6V
19.
horizontal
20
17.
8.0 A
3V
earth
magnetic
field
C
R
A segment of a vertical wire 0.50 m long
carrying a current of 8.0 A is placed in the
earth magnetic field. The direction of the
field dips at an angle of 20 to the horizontal.
If the resulting magnetic force on the wire is
7.5  10-5 N, fmd the flux density of the
earth magnetic field.
6V
Which of the following is/are correct for the
above circuit at steady state?
(1) The current in the circuit is zero.
(2) The voltage across C is independent of
its capacitance.
(3) The voltage across C is independent of
the resistance of R.
A.
B.
C.
D.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
P
R
2I
C.
D. 2I
(1) charges
(2) masses
(3) incident velocities
A.
B.
C.
D.
S
Four long straight current-carrying wires
perpendicular to the plane of the paper are
arranged at the comers of a square PQRS as
shown. The same current I flowing in the
same direction along the wires at P, Q and S
while the current flowing along the wire at R
is in the opposite direction. If the wire at P
experiences no net force, find the current
flowing in the wire at R.
A. I / 2
B. I/2
6.4  10-6 T
1.8  10-5 T
2.0  10-5 T
5.5  10-5 T
20. A beam of charged particles passes through
crossed uniform electric and magnetic fields
without deflection. If the electric field is
removed, the beam will split up into several
beams. This splitting may be due to the
particles having different
18.
Q
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
21.
In the above figure, a solenoid P and a metal
ring Q are arranged coaxially and close to
each other. A sinusoidal a.c. varying with
time t as shown in the graph is supplied to
solenoid P.
Which of the following
descriptions is INCORRECT?
07 AL Physics/M.C./P.6
A. From 0 to t1, the current in Q is in
opposite sense to that in P.
B. From tl to t2, Q is attracted towards P.
C. The force on Q is at a maximum at time
tl.
D. The force on Q is zero at time t2.
A.
B.
C.
D.
6 days
9 days
12 days
18 days
25.
22.
A rectangular coil of 50 turns is being
rotated at 300 revolutions per minute in a
uniform magnetic field.
The field is
perpendicular to the coil’s central axis in the
plane of the coil. If the maximum flux
linking each turn of the coil is 5.1  10-3 Wb,
the maximum e.m.f. induced in the coil is
A.
B.
C.
D.
0.2 V
1.3 V
4.0 V
8.0 V
23. An electric motor driven by a constant
voltage d.c. supply is used to raise a load. If
the load is increased, how will each of the
following change correspondingly?
(1) speed of rotation of the armature coil
(2) current in the armature coil
(3) back e.m.f. in the armature coil
A.
B.
C.
D.
(1)
decrease
unchanged
decrease
decrease
(2)
unchanged
increase
increase
increase
(3)
increase
unchanged
unchanged
decrease
24. A radioactive source consists of 64  1012
atoms of nuclide P of half-life 2 days.
Another source consists of 8  1012 atoms of
nuclide Q of half-life 3 days. After how
long will the number of active nuclei in the
two sources be equal? (Assume that the
daughter nuclides of both P and Q are stable.)
A student used a simple pendulum to
measure the acceleration due to gravity g.
He measured the time (t) for 20 oscillations
using various length L of the pendulum. A
plot of t2 against L deviates from the
‘theoretical’ graph (the dashed line). Which
of the following could be a reason?
(1) He used a stop watch which runs
consistently too fast.
(2) He neglected the radius of the pendulum
bob when measuring L.
(3) He miscounted the number of
oscillations such that the time for only
19 oscillations was taken to be t.
A.
B.
C.
D.
(1) only
(2) only
(2) and (3) only
(1), (2) and (3)
26. Two children P and Q are travelling on
kateboards with frictionless rollers towards
each other as shown. Both are moving at a
speed of 1.2 ms-1. The mass of each child
together with a skateboard is 30 kg. Initially
P holds a ball of mass 1.0 kg, he then throws
the ball straight towards Q at a horizontal
velocity of 15 ms-1. After child Q catches
and keeps the ball, what is his velocity? (All
velocities are relative to the ground.)
07 AL Physics/M.C./P.7
A.
B.
C.
D.
0.74 ms-1 to the right
0.74 ms-1 to the left
0.68 ms-1 to the right
0.68 ms-1 to the left
(3) The frequency of oscillation is the same
at all vibrating points of the rope.
A.
B.
C.
D.
27.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
v
30.
earth
Suppose a space craft is launched with an
initial speed v and it eventually enters a
circular orbit near the earth’s surface. If the
launching speed was increased to 2v, the
spacecraft would (Neglect air resistance.)
A. revolve uniformly in a circular orbit
around the earth with a longer period.
B. revolve uniformly in a circular orbit
around the earth with a shorter period.
C. revolve in an elliptical orbit around the
earth with a longer period.
D. leave the earth and travel to outer space.
A beam of unpolarized light of intensity I
passes normally through two polaroids P
and Q aligned parallel to each other. The
polarizing axis of each polaroid is
represented by an arrow. The polarizing
axis of P is vertical while that of Q makes
60 with the vertical. What is the intensity
of the transmitted beam detected by the
observer, assuming that the only absorption
mechanism is due to polarization?
A.
28. It is known that a geostationary
communication satellite is at a height of
5.6R above the earth’s surface where R is the
radius of the earth. Which of the following
is the best estimate for the separation
between the moon and the earth?
B.
C.
D.
A.
B.
C.
D.
50 R
60 R
150 R
180 R
29. A uniform heavy rope hangs freely from a
support. The support is made to oscillate
horizontally with a small amplitude so as to
send transverse waves down the rope. A
standing wave is set up as these waves are
reflected at the free end. Which of the
following statements is/are correct?
(1) The tension is the same throughout the
rope.
(2) The wavelength is the same throughout
the rope.
I
8
I
4
3I
8
I
2
31. Which of the following statements about the
decibel (dB) are correct?
(1) A ten-fold increase in sound intensity is
equivalent to an increase of 10 dB in
sound intensity level.
(2) The sound intensity level in a noisy
restaurant is about 40 dB.
(3) The threshold of pain is about 120 dB in
sound intensity level.
A.
B.
C.
D.
(1) and (2) only .
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
07 AL Physics/M.C./P.8
(3) When R = 4 , the power consumed in
S is at a maximum.
32. Two pipes of lengths 42.6 cm and 41.5 cm
respectively, each closed at one end, give
beats of frequency 5 Hz when sounding their
fundamental notes together. Neglecting end
corrections, find the speed of sound in air.
A.
B.
C.
D.
331 ms-1
326 ms-1
321 ms-1
316 ms-1
A.
B.
C.
D.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
35.
33.
P
Q
The above figure shows the trajectory of a
positively charged particle travelling along a
curve from P to Q in an electric field. The
particle is subject to electrostatic forces only.
Which of the following deductions must be
correct?
In the above circuit, a capacitor C is charged
by a 6 V battery of negligible internal
resistance. When switch S is opened, the
ammeter reading drops from an initial value
of 80 A to 20 A in 28 s. Estimate the
capacitance of C.
(1) The curve is one of the field lines in the
field.
(2) P is at a higher electric potential than Q.
(3) The sum of kinetic energy and electrical
potential energy of the particle at P is
equal to that at Q.
A.
B.
C.
D.
(2) only
(3) only
(1) and (2) only
(1) and (3) only
A.
B.
C.
D.
140 F
190 F
270 F
540 F
36.
34.
In the above circuit, the cell has constant
e.m.f. and internal resistance 2.0 . R is a
variable resistor while S is a standard
resistor of resistance 6.0 . Which of the
following conclusions must be correct?
(1) When R = 0, the power output of the
cell is at a maximum.
(2) When R = 2 , the power consumed in
R is at a maximum.
The figure shows a semiconductor specimen
containing negative charge carriers. It has a
constant current flowing to the right and is
perpendicular to a uniform magnetic field
pointing out of the paper. Which of the
following is/are correct for the Hall voltage
developed between the upper and the lower
faces of the specimen?
07 AL Physics/M.C./P.9
(1) The Hall voltage will be reversed if the
specimen is replaced by another
semiconductor containing
positive
charge carriers.
(2) The Hall voltage will become larger if
the specimen is replace by a metallic
specimen of the same dimensions and
carries the same current.
(3) The Hall voltage will become smaller if
the separation t between the upper and
lower faces is reduced while the current
is kept unchanged.
A.
B.
C.
D.
A.
B.
C.
D
39.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
The above figure shows an LC circuit in
which P, Q are the input terminals and R, S
are the output terminals. Which of the
following can be a possible function of this
circuit?
37.
When the sinusoidal a.c. shown in Figure (1)
is applied to a resistor R, it produces heat at
a mean rate P. What is the mean rate of heat
production when a square wave a.c. of the
same frequency and amplitude shown in
Figure (2) is applied to the same resistor R?
2P
A.
B. 2P
(1) only
(3) only
(1) and (2) only
(2) and (3) only
A. It blocks the steady d.c. component and
gives low frequency a.c. output.
B. It blocks the steady d.c. component and
gives high frequency a.c. output.
C. It blocks the low frequency a.c.
component and gives high frequency a.c.
output.
D. It blocks the high frequency a.c.
component and gives nearly steady d.c.
output.
40.
Energy
E4
E3
E2
C. 2 2 P
D. 4P
E1
38. An inductor has an inductance of 1 H.
Which of the following deductions must be
correct?
(1) It has a flux linkage of 1 Wb when a
current of 1 A flowing through it.
(2) It stores 1 J of energy when it has a flux
linkage of 1 Wb.
(3) It loses all its magnetic flux in 1 s when
it is connected to a resistor of resistance
1 .
The above figure, drawn to scale, represents
the energy levels for an electron in a certain
atom. The transition from E3 to E1 gives a
green line (in the spectrum). Which of the
following transitions may give a red line?
A.
B.
C.
D.
E4 to E1
E4 to E2
E3 to E2
E2 to E1
07 AL Physics/M.C./P.10
41. The work function W of five metals are
tabulated below.
Metal
W/10-19 J
Caesium
3.4
Calcium
4.6
Barium
4.0
Magnesium
5.9
Beryllium
8.0
If monochromatic light of wavelength 400
nm is incident on each of the metals, how
many of them would exhibit photoelectric
effect?
(Given: Planck constant = 6.6  10-34 J s)
A.
B.
C.
D.
43. Four uniform wires A, B, C and D are loaded
with different weights W and the resulting
extensions x are given below. Which wire
stores the greatest amount of elastic
potential energy? (Assume that the wires
obey Hooke’s law.)
1
2
3
4
A.
B.
C.
D.
x
7 mm
6 mm
5 mm
3 mm
44. Which of the following thermodynamic
processes on a fixed mass of an ideal gas is
IMPOSSIBLE?
A. It absorbs heat and expands while its
internal energy increases.
B. It absorbs heat and expands while its
internal energy decreases.
C. It liberates heat and is compressed while
its internal energy increases.
D. It absorbs heat and is compressed while
its internal energy decreases.
42.
F
0
W
10 N
15 N
20 N
25 N
e
A wire of known cross-sectional area is
stretched by a steadily increasing force and
the force is then slowly reduced. A graph of
the stretching force F is plotted against the
extension e. Which of the following can be
found using information from the graph?
45. Which of the following statements about adecay is/are correct?
(1) Some heavy nuclei tend to increase their
neutron-proton ratio (N/Z) through decay.
(2) -decay shows that -particle is stable.
(3) The mass of a radioactive nucleus is
less than the sum of the masses of the
daughter nucleus and the -particle.
(1) the elastic limit of the wire
(2) the force constant of the wire
(3) the breaking stress for the wire
A.
B.
C.
D.
A. (2) only
B. (1) and (2) only
C. (1) and (3) only
D. (2) and (3) only
END OF PAPER
(1) only
(3) only
(1) and (2) only
(2) and (3) only
07 AL Physics/M.C./P.11
Question No.
Key
Question No.
Key
1.
2.
3.
4.
5.
(53)
(54)
(60)
(75)
(51)
26.
27.
28.
29.
30.
(51)
(58)
(67)
(54)
(40)
6.
7.
8.
9.
10.
(52)
(38)
(35)
(79)
(42)
31.
32.
33.
34.
35.
(62)
(69)
(77)
(38)
(23)
11.
12.
13.
14.
15.
(53)
(77)
(51)
(55)
(19)
36.
37.
38.
39.
40.
(29)
(78)
(46)
(47)
(35)
16.
17.
18.
19.
20.
(39)
(41)
(82)
(56)
(52)
41.
42.
43.
44.
45.
(48)
(30)
(56)
(67)
(54)
21.
22.
23.
24.
25.
(25)
(81)
(42)
(63)
(66)