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98 AL Physics/M.C./P.1
1998 Hong Kong Advanced Level Examination
AL Physics
Multiple Choice Question
1.
3.
P
0.5 kg
Two identical light springs are connected
with two masses of 1.0 kg and 0.5 kg as
shown. Which of the following statements
is/are correct?
A.
(1) The tension in the upper spring is
double that in the lower spring.
(2) The force acting on the ceiling by the
whole system is 15 N.
(3) The tension in the upper spring will
remain unchanged if the two masses
are exchanged in position.
C.
2.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
B
Q
Two blocks A and B of mass ratio 1:2 are
placed on a horizontal frictionless surface
as shown above. P and Q are horizontal
forces acting on A and B respectively (with
P > Q) so that the blocks move to the right
with constant acceleration. Find the force
acting on B by A.
1.0 kg
A.
B.
C.
D.
E.
A
B.
D.
E.
PQ
3
PQ
3
2( P  Q)
3
2P  Q
3
P  2Q
3
4.
final
momentum
North
45
initial
momentum
The velocities of the longitudinal and
transverse waves produced by an
earthquake are 5.0 kms-1 and 9.0 kms-1
respectively. A seismograph records the
arrival of the transverse waves 64 s before
that of the longitudinal waves. How far
away was the earthquake?
The initial momentum of an object is 2
Ns in the direction of S 45 E and its final
momentum is 1 Ns due east. If this change
takes place in 0.5 s, the average force
acting on the object during the change is
A.
B.
C.
D.
E.
A.
B.
C.
D.
E.
256 km
320 km
576 km
659 km
720 km
1 N due north
1 N due south
0.5 N due north
2 N due south
2 N due north
98 AL Physics/M.C./P.2
5.
(1) The kinetic energy of B is four times
that of A.
(2) The frictional force acting on B is
double that acting on A.
(3) If the angular speed of the turntable
gradually increases, B will slip before
A.
F/N
4
0
5
A.
B.
C.
D.
E.
t/s
The graph shows the time variation of the
net force, F, acting on an object of mass 1
kg. The object is initially at rest and its
subsequent motion is along a straight line.
Which of the following statements is/are
correct?
8.
(1) The object is accelerating in the first 5
seconds.
(2) The maximum speed of the object is
less than 10 ms-1.
(3) The final speed of the object is zero.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
A body hanging on a light spring oscillates
vertically between levels X and Z as shown
below. Its static equilibrium position is at
level Y.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
Z
Y
X
6.
A small object is thrown horizontally
towards a vertical wall 1.2 m away. It hits
the wall 0.8 m below its initial horizontal
level. At what speed does the object hit
the wall? (Neglect air resistance.)
Which of the following statements is/are
correct?
(1) The accelerating of the body is zero
when it is at level X.
(2) The strain energy of the spring is zero
when the body is at level Y.
(3) The net downward force acting on the
body is at its maximum when it is at
level Z.
wall
1.2 m
0.8 m
A.
B.
C.
D.
E.
A.
B.
C.
D.
E.
-1
2 ms
3 ms-1
4 ms-1
5 ms-1
7 ms-1
9.
7.
Two small identical coins A and B are
placed on a horizontal turntable which is
kept rotating at a constant angular speed
about a vertical axis through its centre.
The distance of B from the axis of rotation
is twice that of A from the axis. Which of
the following statements is/are correct?
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
A mass is suspended by a light spring
fixed to the ceiling. When the mass-spring
system undergoes vertical oscillation
freely, its frequency is f0. If the system is
removed from the ceiling and forced to
oscillate vertically by a periodic driving
force by variable frequencies, which of the
following graphs best represents the
relationship between its frequency of
98 AL Physics/M.C./P.3
oscillation, f, and the applied frequency,
fa?
E.
f
A.
f
0
0
f0
fa
fa
f0
10. Which of the following travel(s) with the
speed of light in vacuum?
B.
f
0
(1) cathode rays
(2) -rays
(3) ultra violet radiation
f0
fa
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
11. The displacement-time graphs of two
oscillating particles P and Q are shown
below.
C.
f
Displacement
P
Time
0
0
f0
fa
Q
D.
f
0
Which of the following phase relations
between P and Q is correct?
f0
fa

4

P leads Q by
2
P leads Q by .

Q leads P by
4

Q leads P by
2
A. P leads Q by
.
B.
.
C.
D.
E.
.
.
98 AL Physics/M.C./P.4
12. A beam of red (R) light and violet (V) light
strikes normally on a diffraction grating.
Several orders of diffraction of the light
beam are produced on each side of the
central axis. The wavelength of the red
light is 700 nm and that of the violet light
is 400 nm. How will the second- and
third- order diffracted beams of both
colours appear? (The central axis is
marked with a dot and the diffracted
beams of other orders are not shown.)
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
14.
B
D
i
Central axis
V
R V
R
A
A.
medium X
medium Y
C
V
V R
R
B.
V
R R
V
R
R V
V
R
V R
V
C.
D.
E.
13.
B
A
C
D
The above figure shows a transverse wave
propagating along a string. At the instant
shown, the particle D on the string is
moving downward.
Which of the
following deductions is/are correct?
(1) The wave is propagating to the left.
(2) Particle B takes longer than particle A
to return for the first time to the
respective equilibrium positions along
the dotted line.
(3) Particles C and D are moving in
opposite directions at the instant
shown.
A wave is incident on a boundary between
two media X and Y at an angle of
incidence i. AB represents the incident
wavefront and CD the refracted wavefront.
Which of the following statements is/are
correct?
(1) The frequency of the wave changes
when passing from X to Y.
(2) The end B of the wavefront travels to
D at the same time as the end A
travels to C.
(3) When angle i increases, it is possible
for the wavefront to be totally
reflected at the boundary.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
15. Sunlight is scattered by air molecules in
the atmosphere. Which of the following
statements concerning this process is/are
correct?
(1) Light is absorbed by air molecules
and is then re-emitted.
(2) The scattered light observed on the
earth’s surface is partially planepolarized.
(3) Red light is scattered more than blue
light is.
98 AL Physics/M.C./P.5
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
A.
B.
C.
D.
E.
16.
On the surface of the earth
3.4  108 m from the earth
1.9  108 m from the earth
0.4  108 m from the earth
On the surface of the moon
18.
L2
L1
L3
water
In the above circuit, light bulbs L1, L2 and
L3 consume power at the rate 1:1:3. If the
resistance of L3 is R, the resistance of L1 is
tap
The above figure shows a long vertical
glass tube containing water. The water
level is lowered until the first resonance
occurs when a vibrating tuning fork is
placed at the opening of the tube. Which
of the following statements is/are correct?
(Neglect end corrections.)
(1) The sound produced by the air
column above the water has the same
frequency as the tuning fork.
(2) Resonance will occur again if the
length of the air column above the
water is increased to three times its
original value.
(3) Resonance will occur again if another
tuning fork of twice the frequency is
used.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
17. The mass ratio of the earth and the moon
is 81:1 and the earth-moon separation is
3.8  108 m. At which position between
the earth and the moon is the gravitational
potential at a maximum? (Ignore all other
planets.)
A.
B.
C.
D.
E.
3R/16
R/4
3R/4
4R/9
3R
19.
current/A
5.0
1.0
0
1.0
2.0 voltage/V
The variation of current with the voltage
applied across a device is as shown. What
is the change in resistance of the device
when the voltage increases from 1.0 V to
2.0 V?
A.
B.
C.
D.
E.
It decreases by 0.25 
It increases by 0.25 
It decreases by 1.50 
It increases by 0.60 
It decreases by 0.60 
98 AL Physics/M.C./P.6
20.
A.
2.0 V
E
S
0.8 H
0
4.0 
Q
B.
E
A coil of inductance 0.8 H is connected in
series with a switch S and a cell of e.m.f.
2.0 V. The total resistance of the circuit is
4.0 . What is the initial rate of growth of
the current when the switch is closed?
A.
B.
C.
D.
E.
0
0 As-1
0.4 As-1
0.5 As-1
1.6 As-1
2.5 As-1
Q
C.
E
21.
0
10 k
Q
D.
E
6V
5 k
2V
V
voltmeter, 5 k
In the above circuit each cell has
negligible internal resistance.
The
voltmeter has a resistance of 5 k. The
reading on the voltmeter is
A.
B.
C.
D.
E.
0V
1.0 V
1.2 V
1.5 V
2.0 V
22. Which of the following graphs shows
correctly the relationship between the
energy E stored in an isolated conducting
sphere and the charge Q on it?
0
Q
E.
E
0
Q
98 AL Physics/M.C./P.7
23.
E.
A
C
V
R
B
VR
0
24.
R
B.
A charged capacitor C1, is connected to an
uncharged capacitor C2 of larger
capacitance through a resistor R as shown
above. When switch S is closed, which of
the following statement is INCORRECT?
A. The total charges on the two
capacitors remain unchanged.
B. The final charge on C2 is greater than
that on C1.
C. The potential difference across C1
falls.
D. The potential difference across the
two capacitors finally becomes equal.
E. The total energy stored in the two
capacitors remains the same.
t
VR
0
S
C2
VR
0
C1
t
A changing voltage V is applied across AB
in the circuit shown.
The potential
difference VAC across the capacitor is
found to vary with time t as shown.
Which of the following graphs shows the
variation of potential difference VR across
the resistor R with time t?
A.
t
D
VAC
0
VR
t
25.
current /A
C.
5.0
VR
time/ms
0
0
t
2
3
4
5
An alternating current flowing through a
resistor varies with time as shown above.
What is the value of the direct current that
gives the same heating effect as the
alternating current?
D.
VR
0
1
-3.0
t
A.
B.
C.
D.
E.
3.9 A
4.0 A
4.1 A
4.2 A
4.3 A
98 AL Physics/M.C./P.8
26.
E.
T
v
0
The figure shows a charged particle
moving in a circle with constant speed v
on a plane perpendicular to a uniform
magnetic field. Which of the following
graphs represents the relation between the
time T for the particle to complete a circle
and its speed v?
27.
P
r
r
A.
T
0
current I
into paper
r
Two long, straight parallel conducting
wires, each carrying a current I, are
separated by a distance r as shown. What
is the magnetic field at a point P at the
same distance r from both wires? (0 =
permeability of free space)
v
B.
T
A.
B.
0
v
C.
C.
T
D.
E.
0
v
0I
to the left
2r
3 0 I
to the left
2r
0I
to the left
r
3 0 I
to the right
2r
0I
to the right
2r
28.
D.
T
R
0
v
C
L
The root-mean-square voltages across the
resistor R, capacitor C and inductor L of
an RCL series circuit are respectively 4 V,
1 V and 4 V. What is the phase difference
between the applied voltage and the
current flowing in the circuit?
98 AL Physics/M.C./P.9
A.
B.
C.
D.
E.
31.
30
37
45
53
60
-particle
29. A capacitor has a capacitance of 1 farad.
Which of the following deductions must
be correct?
-particle
The above diagram shows two -particles
moving directly towards each other with
the same speed. Which of the following
statement is/are correct?
(1) It stores 1 coulomb of charge at a
potential difference of 1 volt.
(2) It gains 1 joule of electrical energy
when it has 1 coulomb of charge.
(3) It will be fully charged in 1 second by
a constant current of 1 ampere.
(1) The two particles attract one another.
(2) The electric potential energy of the
two particles is decreasing at the
instant shown.
(3) The total momentum of the two
particles remains constant in the
subsequent motion.
A.
B.
C.
D.
E.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
32. Which of the following is/are random
process(es)?
30.
B
A
N
C
S
D
The above diagram shows a rectangular
current-carrying coil ABCD in a uniform
magnetic field between two pole pieces.
The magnetic field is perpendicular to the
plane of the coil. Which of the following
statements is/are correct?
(1) There is a magnetic force acting on
the side BC of the coil.
(2) The magnetic forces acting on the coil
tend to reduce its area.
(3) The coil will return quickly to its
original vertical position when it is
disturbed slightly.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(1) The
background
radiation
in
radioactivity.
(2) The Brownian motion of smoke
particles in a smoke cell.
(3) The scattering of -particles by the
nuclei in a piece of gold foil.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
33. The internal energy of an ideal gas always
changes when
(1) its volume increases.
(2) it undergoes an isothermal change.
(3) it is compressed in an insulating
container.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
34. In which of the following cases will heat
always flow away from a body X?
98 AL Physics/M.C./P.10
Force
(1) X is changed from its liquid state to a
solid at freezing point.
(2) X is in thermal contact with another
system at a lower temperature.
(3) X is in thermal contact with another
system which has a smaller amount of
internal energy.
A.
B.
C.
D.
E.
0
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
Separation
P
Q
The figure shows the force-separation
graph for a pair of atoms in a material.
Which of the following features is most
closely related to the stiffness and the
tensile strength of the material?
35. The root-mean-square speed of a sample
of helium gas molecules, each of mass m,
is c. Which of the following deductions is
correct?
(1) the value of the separation at P
(2) the value of the separation at Q
(3) the value of the slope of the graph at
P
(4) the value of the force at Q
A. The
percentage
of
molecules
travelling at speed c is greater than at
other speeds.
B. Half of the molecules travel at a speed
higher than c.
C. All molecules travel randomly with
speed c.
D. The average speed of the molecules is
c.
E. The average kinetic energy of the
molecules is ½mc2.
Stiffness
(1)
(1)
(3)
(3)
(4)
A.
B.
C.
D.
E.
Tensile strength
(2)
(4)
(2)
(4)
(3)
38.
screen
36. A uniform vertical steel wire is stretched
by hanging a weight from its lower end.
Which of the following would put a
greater strain on the wire? (The Young
modulus of steel is greater than that of
brass.)
V
d
filament
A.
B.
C.
D.
E.
37.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
deflection
Q
electron gun
(1) Using a steel wire of greater
unstretched length.
(2) Using a steel wire of greater crosssectional area.
(3) Replacing the steel wire with a brass
wire of the same unstretched length
and cross-sectional area.
P
anode
L
In a cathode ray tube, the beam of
electrons from the electron gun is
deflected vertically when a p.d. is applied
between the deflection plates, P and Q, of
length L and separation d. Which of the
following changes will increase the
deflection of the beam for a given p.d.
across the deflection plates?
(1) Reducing the p.d. V between the
filament and the anode.
(2) Reducing the separation d between
the deflection plates.
(3) Reducing the length L of the
deflection plates.
98 AL Physics/M.C./P.11
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
A.
B.
C.
D.
E.
39.
41. The activity of a sample of radioactive
isotopes decreases to 1/3 of its initial value
in 12 s. How much more time would be
required for the activity to decrease to 1/9
of its initial value?
S
V
In the above circuit, the resistors are
identical, the battery has negligible
internal resistance and the voltmeter draws
negligible current. What are the possible
voltmeter readings before and after closing
switch S?
S open
A.
B.
C.
D.
E.
2V
2V
0V
4V
4V
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
S closed
A.
B.
C.
D.
E.
4s
8s
12 s
16 s
24 s
42.
Energy
4V
2V
4V
0V
2V
P
X
40.
T
V+
LDR
R1
_
Vout
+
R3
V-
R
R2
0V
In the above circuit, the output voltage
from the operational amplifier is positive.
Which of the following changes could
cause the output voltage to change to
negative?
(1) Increasing the value of R1.
(2) Decreasing the value of R3.
(3) Decreasing the light intensity on the
LDR.
Q
S
The diagram shows some energy levels
(drawn to scale) of a certain atom.
Transition X results in the emission of a
photon of wavelength 600 nm. Which
transition (P to T) would result in the
emission of a photon of wavelength 300
nm?
A.
B.
C.
D.
E.
P
Q
R
S
T
98 AL Physics/M.C./P.12
43. A radioactive sample, initially consists of
only nuclide X, decays by the emission of
an alpha particle to form a stable daughter
nuclide Y.
Which of the following
quantities will decrease with time?
(1) The rate of decay of nuclide X.
(2) The rate of growth of nuclide Y.
(3) The rate of emission of alpha
particles.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
44. When several neutrons and protons come
together to form a stable nucleus, which of
the following statements is/are correct?
(1) Energy is released.
(2) The mass of the nucleus is smaller
than the sum of the mass of the
individual nucleons.
(3) In the nucleus, the electrostatic
repulsion between two protons is
overcome by the nuclear force
between them.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
45. In a nuclear reactor, the 235
92 U nucleus is
fissioned by a neutron into two nuclei and
a few neutrons are produced. Which of
the following statements about this process
is/are correct?
(1) High energy neutrons are more likely
to produce nuclear fission than low
energy neutrons.
(2) Graphite can be used to absorb excess
neutrons.
(3) The two nuclei produced have smaller
neutron-to-proton ratios than that of
the uranium nucleus.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
98 AL Physics/M.C./P.13
Question No.
Key
Question No.
Key
1.
2.
3.
4.
5.
D
E
D
E
C
26.
27.
28.
29.
30.
B
D
B
A
C
6.
7.
8.
9.
10.
D
E
B
D
D
31.
32.
33.
34.
35.
B
C
B
C
E
11.
12.
13.
14.
15.
A
B
A
D
C
36.
37.
38.
39.
40.
B
D
C
A
D
16.
17.
18.
19.
20.
C
B
A
E
E
41.
42.
43.
44.
45.
C
B
E
E
B
21.
22.
23.
24.
25.
A
A
A
E
C