Download 05mc

05 AL Physics/M.C./P.1
2005 Hong Kong Advanced Level Examination
AL Physics
Multiple Choice Questions
1.
4.
30 cm
40 cm
(1) the positions of the five objects in the
air at any instant before landing on
the ground,
(2) the landing positions of the five
objects on the ground?
A block of mass 2.5 kg rests on the rough
surface of a wedge, which in turn rests on
a rough horizontal floor as shown.
What is the frictional force exerted by the
floor on the wedge if the whole system is
at rest?
A.
B.
C.
D.
2.
Five objects are released from an aircraft
flying horizontally with a constant
velocity. They are released one by one at
two-second intervals.
Neglecting air
resistance, what can be said about
(1)
A. They lie on a
parabola
B. They lie on a
parabola
C. They lie on a
straight line
D. They lie on a
straight line
0N
12 N
15 N
20 N
The figure shows a pendulum bob
swinging between positions x and y.
5.
x
P
y
Q
R
z
S
Which of the arrows P, Q, R, S represents
the direction of the resultant force acting
on the bob when the bob is at position z?
(Neglect air resistance.)
A horizontal elastic cord of natural length
a is fixed at one end and a small mass m is
attached to the other end. The mass
rotates uniformly in a horizontal circle on
a smooth horizontal surface. When the
mass takes time T to complete one
revolution, the length of the cord is 1.5a.
The angular speed of the mass is changed
such that the length of the cord becomes
2a. What is the new time for one
revolution? (Assume that the elastic cord
obeys Hooke’s law.)
A.
A.
B.
C.
D.
3.
(2)
They are evenly
spaced.
They are unevenly
spaced.
They are evenly
spaced.
They are unevenly
spaced.
P
Q
R
S
An object falls from rest from the top of a
tower. The object takes 0.40 s to fall
from the mid-point of the tower to the
ground. Calculate the time taken for the
object to fall from the top of the tower to
the ground. (Neglect air resistance.)
A.
B.
C.
D.
0.68 s
0.80 s
1.20 s
1.37 s
B.
C.
D.
2
T
3
4
T
3
2
T
3
3
T
2
6.
P
O
Q
An object performs simple harmonic
motion along a straight line about the
equilibrium position O. It passes points
P and Q with the same speed. The object
05 AL Physics/M.C./P.2
takes 0.2 s to travel from P to Q and it
takes a further 0.3 s to return to P. What
is the period of the motion?
A.
B.
C.
D.
7.
9.
0.6 s
0.8 s
1.0 s
1.2 s
A convex lens of focal length 20 cm forms
a diminished image of an object (letter ‘F’)
on a translucent screen, as shown.
Which of the following deductions is/are
correct?
Two blocks P and Q are joined by a light
inextensible cord. The two blocks are
attached to fixed points by means of two
light identical springs as shown. The
mass of P is greater than that of Q. The
blocks rest on a smooth horizontal surface
and the cord is in tension.
P
cord
(1) The separation of the lens and the
screen is less than 40 cm.
(2) The separation of the object and the
screen is greater than 80 cm.
(3) Keeping the positions of the object
and the screen unchanged, another
sharp image can also be formed on
the screen if the lens is moved nearer
to the object.
Q
When the cord is cut, the two blocks
subsequently perform simple harmonic
motion.
Which of the following
statements about block P is/are correct?
(1) It has a longer period.
(2) It has a smaller amplitude.
(3) It has a smaller maximum kinetic
energy.
A.
B.
C.
D.
(1) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
10.
P
A.
B.
C.
D.
(1) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
S1
8.
direction of propagation
P
Q
R
The figure shows the shape of a transverse
wave travelling along a string at a certain
instant.
Which of the following
statements about the motion of the
particles P, Q and R on the string at this
instant is correct?
A. Particle P is moving downwards.
B. Particle Q is stationary.
C. Particle R has at its maximum
acceleration.
D. Particles P and Q are in phase.
S2
In the figure, S1 and S2 are two dippers in
a ripple tank generating circular waves of
wavelengths l and 2 respectively with 1
= 22. The solid lines represent crests.
S1 and S2 are generating crests at the
instant shown. P is a point equidistant
from S1 and S2. Which of the following
statements is correct?
A. The frequency of the waves generated
by S1 is twice that of S2.
B. The waves at P always reinforce each
other.
C. The waves at P do not obey the
principle of superposition as their
wavelengths are not equal.
D. The waves at P still obey the principle
of superposition but they do not
always reinforce each other.
05 AL Physics/M.C./P.3
11.
(1) Disconnecting the plates from the
supply and moving the plates closer
(2) Keeping the separation between the
plates unchanged and increasing the
p.d. between the plates
(3) Keeping the p.d. between the plates
unchanged and moving the plates
further apart
cladding (n2)
i
core (n1)
The figure shows the structure of an
optical fibre. It consists of an inner core
of refractive index nl and an outer
cladding of refractive index n2. Which of
the following conditions is necessary for
the ray to travel along the core of the
fibre?
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
14.
A. nl > n2 and the angle i should be
greater than a certain value.
B. nl > n2 and the angle i should be less
than a certain value.
C. nl < n2 and the angle i should be
greater than a certain value.
D. nl < n2 and the angle i should be less
than a certain value.
R
mA
A voltmeter is constructed by connecting a
resistor R in series with a milliammeter of
negligible internal resistance as shown.
It is found that this voltmeter reads 4.9 V
when the actual value is 5.0 V. Which of
the following modifications would
improve the accuracy of the voltmeter
such that it gives a reading close to 5.0 V?
12. P, Q and R are small identical metal
spheres. P and Q are fixed at a certain
separation in vacuum and they carry
charges of the same magnitude. The
attractive force between them is F.
Sphere R is initially uncharged. It first
touches P and then it touches Q. What is
the electrostatic force between P and Q
after R is taken away?
A.
B.
C.
D.
A. Connecting
a
resistance is much
series with R
B. Connecting
a
resistance is much
series with R
C. Connecting
a
resistance is much
parallel with R
D. Connecting
a
resistance is much
parallel with R
F/4
F/8
3F/4
3F/8
13.
+
resistor
whose
higher than R in
resistor
whose
lower than R in
resistor
whose
higher than R in
resistor
whose
lower than R in
15.
4 k
_
10 V
6 k
2 F
2 F
K
A negatively charged oil drop is kept
stationary between two horizontal metal
plates connected to a d.c. supply as shown.
The oil drop then acquires an additional
negative charge. Which of the following
changes will be able to hold the oil drop
stationary?
In the circuit, the battery has a constant
e.m.f. of 10 V and negligible internal
resistance. Initially, switch K is closed.
The switch K is then opened. What is the
05 AL Physics/M.C./P.4
total additional charge given to the two
capacitors when a steady state is reached?
A.
B.
C.
D.
18.
-particle’s path
8 C
12 C
28 C
40 C
W
Z
Magnetic
field out
of paper
16.

R

 Q














S


P

uniform
magnetic
field
X
proton’s path
A proton and an -particle move in a
uniform magnetic field. The magnetic
field is directed out of the plane of the
paper. Within a square region WXYZ, the
proton takes time t1 to complete a half
circle from X to Y while the -particle
follows a quarter circle from X to Z in
time t2. What is the ratio t1 : t2 ?
Conducting rods PQ and RS are placed on
two
smooth,
parallel,
horizontal
conducting rails. A uniform magnetic
field is directed into the plane of the paper.
PQ is given an initial velocity to the right.
Which of the following statements is
INCORRECT?
A. The induced current is in the direction
PQRS.
B. The magnetic force acting on rod PQ
is towards the left.
C. Rod RS starts moving towards the
right.
D. Rod PQ moves with a uniform speed.
Y
A.
B.
C.
D.
1:2
1:1
2:1
It cannot be determined as the ratio of
their speeds is not given.
19. A rectangular coil is placed adjacent to a
straight wire MN carrying an alternating
current I which varies with time t as
shown in the graph. The wire MN is in
the plane of the coil and the current I is
positive (+) when it is in the direction
from M to N.
17.
N
2
dynamo
In the circuit, the two ‘12 V, 6 W’ lamps
are operating at their rated values. The
internal resistance of the dynamo is 2 .
What percentage of the electrical power
generated by the dynamo is consumed by
the two lamps?
A.
B.
C.
D.
75%
86%
92%
100%
+
_
I
0
t
T/2
T
M
Starting from t = 0, how does the direction
of the current induced in the coil vary in
one period?
A. Clockwise
first
and
then
anticlockwise
B. Anticlockwise
first
and
then
clockwise
C. Clockwise  anticlockwise 
clockwise  anticlockwise
D. Anticlockwise  clockwise 
anticlockwise  clockwise
05 AL Physics/M.C./P.5
20. Two vessels contain hydrogen gas and
oxygen gas respectively. Both gases are
assumed to be ideal and they have the
same pressure and temperature. Which
of the following physical quantities must
be the same for the two gases?
A.
B.
C.
D.
The volume of the gas
The mass per unit volume of the gas
The r.m.s. speed of the gas molecules
The number of gas molecules per unit
volume
A.
B.
C.
D.
21.
Pressure
160 counts per second
80 counts per second
60 counts per second
30 counts per second
Y
1.5p
24. On which of the following does the
activity of a radioactive source depend?
p
X
0
T
2T
Absolute
temperature
A gas in a vessel of fixed volume leaks
gradually. The gas in the vessel changes
from state X to state Y along the path XY
shown in the plot of pressure against
absolute temperature. What percentage
of the original mass of the gas leaks out
from the vessel in this process?
A.
B.
C.
D.
23. A detector placed near a source of gamma
radiation records a count rate of 960
counts per second. The half-life of the
source is 12 hours. A slab of material of
thickness 6 cm is then placed between the
source and the detector. The ‘half-value
thickness’ of the material is 2 cm (i.e.
the intensity of the radiation would reduce
by half after passing through 2 cm of the
material).
Estimate the count rate
recorded by the detector after one day.
(Neglect any background radiation.)
(1) the number of active nuclides in the
source
(2) the half-life of the source
(3) the nature of the nuclear radiation
emitted by the source
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
25. A physical quantity x is measured many
times. The number of measurements N
giving a value of x is plotted against x.
The ‘true’ value of the physical quantity is
x0. Which graph below shows that the
measurements have small random errors
but a large systematic error?
10%
20%
25%
50%
22. The following equation represents a
nuclear fission reaction, producing q
neutrons.
A.
N
235
1
141
92
1
92 U0 n 56 Ba  Z K q 0 n
What are the values of the atomic number
Z and the number q?
x
0
A.
B.
C.
D.
Z
37
36
36
34
q
2
2
3
3
x0
B.
N
x
0
x0
05 AL Physics/M.C./P.6
flywheel is dissipated against friction in
the journey, find the maximum height
reached by the toy car.
C.
N
A.
B.
C.
D.
5.5 cm
7.5 cm
9.5 cm
It cannot be determined as the angle
of inclination is not known.
x
0
x0
28. An object of mass 5.0 kg has a weight of
8.2 N on the surface of the moon. The
radius of the moon is R. What is the
gravitational field strength, in N kg-1, at a
point distance 2R from the centre of the
moon? (Assume that the moon is a sphere
of uniform density.)
D.
N
A.
B.
C.
D.
x
0
x0
1.6
0.8
0.4
0.2
26.
U
29.
P
X 2 mm
0
Y
x
The graph shows how the potential energy
(U) of a body varies with its displacement
(x) from a fixed point. Which feature of
the graph shows that the force acting on
the body is directed towards the fixed
point?
A. The fact that the graph passes through
the origin.
B. The fact that the value of the potential
energy is always positive.
C. The fact that the graph is symmetrical
about the U-axis.
D. The fact that the potential energy
increases as the body moves further
away from the fixed point.
27. A toy car is equipped with a small
flywheel that can be set into rapid rotation
by a brief push across a solid surface.
The moment of inertia of the flywheel is
3.6  10-5 kg m2 and the total mass of the
toy car is 0.2 kg. With the flywheel
rotating at an angular velocity of 96 rad s-1,
the car is allowed to run up an incline. If
10% of the energy initially stored in the
45 cm
Two identical sinusoidal waves, travelling
in opposite directions along a string XY
fixed at both ends, form a stationary wave.
The separation between X and Y is 45 cm.
The figure shows the shape of the string at
an instant when the antinode P attains its
maximum displacement of 2 mm from the
equilibrium position.
What is the
amplitude and wavelength of each of the
travelling waves on the string?
A.
B.
C.
D.
Amplitude
1 mm
1 mm
2 mm
2 mm
Wavelength
30 cm
15 cm
30 cm
15 cm
05 AL Physics/M.C./P.7
30. In the figure, XY is an optically flat glass
plate while PQ is a glass specimen with a
uniform indentation along PQ. When
monochromatic light of wavelength  falls
normally on the system, interference
fringes are observed as shown. The
maximum depth of the indentation is h.
What is the value of h, in terms of a, b and
? (Diagram not drawn to scale.)
32. The figure shows the essential features of
a cathode-ray tube with filament F,
cathode and anode.
Monochromatic
light
Y
P
Q
X
b
P
Q
A.
B.
C.
D.
a
h = b / 2a
h = b / a
h = 2b / a
h = (a - b) / 2a
(1) Increasing the p.d. between the plates
P and Q
(2) Increasing the p.d. between the anode
and cathode
(3) Increasing the p.d. applied across the
filament F
31.
Metal
plate
Transmitter
Q
P
Probe detector
A
microwave
transmitter
emits
plane-polarized waves of frequency 1.0 
1010 Hz which are reflected from a large
metal plate as shown. When a probe
detector is moved between P and Q, the
intensity of the waves detected varies
along the line PQ.
Which of the
following statements is/are correct?
(1) The variation in intensity is due to the
interference of waves.
(2) The separation between consecutive
positions of minimum intensity is 3
cm.
(3) If the transmitter is rotated 90 about
the line PQ, a position of minimum
intensity will become a position of
maximum intensity.
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
A beam of electrons emitted from the
cathode is deflected by the electric field
between the plates P and Q. Which of
the following changes will increase the
deflection of the electron beam?
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
33. A p.d. of 10 V is applied across a uniform
wire of resistance 5.0 . The number of
conduction electrons per unit volume of
the wire is 1.0  1028 m-3 and its
cross-sectional area is 1.0 mm2. What is
the average drift velocity of conduction
electrons in the wire?
(Given: charge on electron = -1.6  10-19
C)
A.
B.
C.
D.
3.l  10-4 m s-1
1.3  10-3 m s-1
3.1  10-3 m s-1
6.3  10-3 m s-1
05 AL Physics/M.C./P.8
34. The electric field strength near the surface
of a charged metal sphere is E. The
charge on the sphere and its radius are
doubled. What is the new electric field
strength near the sphere’s surface?
A.
B.
C.
D.
the induced e.m.f. in L.
the current in L.
the inductance of L.
the energy stored in L.
37. A coil of inductance 3.2  10-2 H and
resistance 20  is connected to a 50 Hz
a.c. source. What is the impedance of
the coil at 50 Hz?
E
4
E
B.
2
C. E
D. 2E
A.
A.
B.
C.
D.
35.
10 
20 
22 
30 
38.
C
R
0.5 m
The figure shows a rectifier circuit with a
smoothing capacitor C which has been
installed to provide current to a load
resistor R. Which of the following would
reduce the ripple on the current through
R?
A wide tank contains a non-viscous liquid.
The surface of the liquid is at a height 0.5
m above a hole situated at the bottom of
the tank. Assuming streamline flow,
calculate the velocity of the liquid
emerging from the hole.
(1) Increasing the capacitance of C
(2) Increasing the resistance of R
(3) Increasing the a.c. supply frequency
A.
B.
C.
D.
A.
B.
C.
D.
(1) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
39. Masses m and 2m are suspended from two
uniform copper wires P and Q. The
wires are of the same length and their
cross-sectional areas are A and 2A
respectively. What is the ratio of the
elastic potential energy stored in wire P to
that in wire Q?
36.
x
E
2.2 m s-1
3.2 m s-1
10 m s-1
It cannot be found as the density of
the liquid is not known.
S
R
L
P
0
A cell of e.m.f. E is connected to a resistor
R and an inductor L as shown. When
switch S is closed, the variation with time
t of a quantity x is represented by the
graph. The quantity x is
Q
t
m
A.
B.
C.
D.
1: 4
2: 1
1:1
1:2
2m
05 AL Physics/M.C./P.9
42. The critical temperatures and boiling
points of carbon dioxide (CO2) and
oxygen (O2) are given below:
40.
F
P
critical
temperature
/ C
Y
Z
X
0
carbon dioxide
(CO2)
oxygen (O2)
e
O
Q
A specimen of material stretches and
contracts as a tensile force F is applied to
it. The force F is first increased (O to P)
and then decreased (P to Q) as shown in
the force-extension (F-e) graph. Which
of the following combinations of areas X,
Y and Z represents the net work done on
the specimen during the stretching and
contracting cycle?
A.
B.
C.
D.
Z
X+Y
X+Y–Z
X+Y+Z
41. The circuit below is constructed using an
ideal operational amplifier.
50 k
Vin
5 k
_
Vout
- 15 V
0.5 V
An input voltage Vin of 0.5 V is applied to
the circuit. What is the potential at the
inverting input and the current in the 50
k resistor?
A.
B.
C.
D.
potential
0V
0V
-5V
-5V
current
10 A
100 A
10 A
100 A
-119
-183
Which of the following statements is/are
correct?
(1) Both carbon dioxide and oxygen are
in a gaseous state at s.t.p. (i.e. 0 C,
1 atm).
(2) Oxygen can be liquefied at –150 C
by increasing the pressure.
(3) Both carbon dioxide and oxygen can
be liquefied at 0 C by increasing the
pressure.
A.
B.
C.
D.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
43. Which of the following descriptions about
spectra is/are correct?
+ 15 V
+
31.1
boiling point at
standard
atmospheric
pressure / C
-78.5
(1) A tungsten-filament lamp emits a
continuous spectrum of light.
(2) An electrical discharge through a gas
at low pressure produces a line
spectrum.
(3) A gas produces an emission spectrum
at high temperatures.
A.
B.
C.
D.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
05 AL Physics/M.C./P.10
44.
n=4
n=3
-1.6 eV
-2.7 eV
n=2
-5.5 eV
n=1
-10.4 eV
The figure shows the possible energy
levels of a mercury atom.
A free
electron with kinetic energy 8.4 eV
collides with a mercury atom, which is in
its ground state. The change in kinetic
energy of the mercury atom in the
collision may be neglected. What is/are
the possible value(s) for the kinetic energy
of the electron after collision?
45. Which of the following phenomena
supports the fact that a nucleus is made up
of other fundamental constituents?
A. emission of electrons when a metal is
illuminated by light
B. the emission of line spectrum by
atoms
C. the scattering of -particles from a
gold foil
D. the decay of radioactive substances
(1) 0.7 eV
(2) 2.9 eV
(3) 3.5 eV
A.
B.
C.
D.
(1) only
(2) only
(2) and (3) only
(1) and (3) only
- End of Paper -
05 AL Physics/M.C./P.11
Question No.
Key
Question No.
Key
1.
2.
3.
4.
5.
A (12)
B (16)
D (33)
C (34)
A (40)
26.
27.
28.
29.
30.
D (54)
B (73)
C (76)
A (62)
A (27)
6.
7.
8.
9.
10.
A (45)
A (56)
C (49)
D (30)
D (56)
31.
32.
33.
34.
35.
A (45)
A (74)
B (78)
B (75)
D (57)
11.
12.
13.
14.
15.
B (46)
B (26)
B (52)
C (The item was deleted)
C (30)
36.
37.
38.
39.
40.
A (66)
C (70)
B (72)
D (42)
B (62)
16.
17.
18.
19.
20.
D (51)
B (67)
B (38)
A (29)
D (58)
41.
42.
43.
44.
45.
B (53)
C (63)
D (34)
D (68)
D (39)
21.
22.
23.
24.
25.
C (83)
C (86)
D (73)
C (61)
A (34)