7.
A transverse wave travels from left to right. The displacement of particles in the
medium varies with position at a particular instant of time is shown below.
Which arrow represents the direction of the velocity of the particle marked P?
8.
Diagram 1 below represents equally spaced beads on a spring. The beads are 1 cm
apart.
Diagram 1
A longitudinal wave propagates along the spring. Diagram 2 shows the position
of the beads at a particular instant.
Diagram 2
Which of the following is the best estimate of the wavelength?
A.
B.
C.
D.
16 cm
8 cm
4 cm
2 cm
9.
A teacher asks the students to tell the differences between water wave and sound wave
transmitted through water. The students make the following comments. Which of them
is incorrect?
A.
In water wave, the energy is transmitted perpendicular to the wave travel
direction but in sound wave, energy is transmitted parallel along the wave travel
direction.
B.
Water wave is transverse wave but sound wave transmitted through water is
longitudinal wave.
C.
Water wave propagates on the water surface but sound wave transmitted through
water propagates in the water.
D. Water wave and sound wave transmitted through water travel with different
speeds.
10. The diagram below shows a pulse travelling along a rope from X to Y. The end Y of
the rope is tied to a fixed support.
When the pulse reaches end Y it will
A.
disappear.
B.
cause the end of the rope at Y to oscillate up and down.
C.
be reflected and be inverted.
D. be reflected and not be inverted.
11.
Which of the following statements is true for a standing wave on a string?
A.
No energy is transferred along the string.
B.
The particles at the nodes have maximum kinetic energy.
C.
Each particle on the string oscillates with different frequency.
D. The amplitude along the string varies with time.
Questions 12 and 13
A laser beam is incident normally on a pair of slits of separation 0.5 mm. Alternative
bright and dark fringes are formed on a screen placed 2 m from the slits, and
within 1 cm, 5 dark fringes can be found as shown in the figure below.
1 cm
12. The wavelength of the laser beam is
A. 5 x 10-7 m.
B. 5.5 x 10-7 m.
C. 6.25 x 10-7 m.
D. 7 x 10-7 m.
13. The screen is then moved closer to the slits. If the distance between the screen and the
slit is reduced to 1 m. How many dark fringes will there be within 1 cm?
A. 10
B. 9
C. 8
D. 3
14. Two circular water waves generated by two vibrating dippers, X and Y, superimpose on
each other in a ripple tank. A student comments that constructive interference occurs at
a position P if the path difference of the position P from the two dippers is equal to an
integral multiple of the wavelength of the water waves.
The student's comment is correct only if
(1) the two dippers vibrate with the same amplitude.
(2) the two dippers vibrate with the same frequency.
(3) the two dippers vibrate in phase
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
15. Which of the following is a value of wavelength of visible light?
A. 4 × 10-5 m
B. 4 × 10-7 m
C. 4 × 10-9 m
D. 4 × 10-11 m
16. What is the best estimate for the refractive index of a medium in which light
travels at a speed of 2.7 × 108 m s-1?
A. 0.9
B. 1.0
C. 1.1
D. 2.7
17. Sound demonstrates interference effect. This is an evidence that
A. sound is a wave.
B. sound is a longitudinal wave.
C. sound is a mechanical wave.
D. sound is a wave that needs a medium for transmission.
18.
A musician plays a violin. The string of the violin vibrates and music transmits through
the air.
Which of the following correctly describes the waves produced?
A. Longitudinal waves are produced in the string and in the air.
B. Transverse waves are produced in the string and in the air.
C. Longitudinal waves are produced in the string and transverse waves are produced
in the air.
D. Transverse waves are produced in the string and longitudinal wave are produced
in the air.
19. Which of the following statements about ultrasound is incorrect?
A. An ultrasound is a mechanical wave.
B. Ultrasound has frequencies higher than 20 kHz
C. Ultrasound cannot travel in vacuum.
D. Ultrasound has the same speed in air and in water.
20. Which of the following statements about ultra-violet and ultrasound is correct?
A. Ultra-violet is invisible to human eyes and ultrasound is inaudible to human ears.
B. Both ultra-violet and ultrasound travel with the speed of light.
C. Both ultra-violet and ultrasound are within the same frequency range.
D. Both ultra-violet and ultrasound can cause cancer.
6.
The figure below shows the displacement-time graph of a particle in a transverse wave.
displacement / mm
1
0.5
0
5
10
time / ms
0.5
1
Find
(a)
the frequency of the wave.
(2 marks)
(b)
the amplitude of the wave.
(1 mark)
(c)
the average speed of the particle.
(2 marks)
7.
equilibrium
positions
time t = 0
direction of travel
of the wave
The above figure shows the equilibrium positions of some particles in a medium and their positions at
time t = 0 when a longitudinal wave passes. Take the displacement to the right to be positive.
(a)
Which of the particles is at the centre of rarefaction?
(1 mark)
(b)
What is the amplitude of the wave?
(1 mark)
(c)
Which particles, A, B, C, D, E and F, is/are moving to the right at time t = 0?
(1 mark)
(d)
Sketch the displacement-time graph of particle A from t = 0 to T where T is the period of the wave.
(2 marks)
8. A string under tension is attached at two rigid supports, P and Q, and is made to vibrate at its
fundamental frequency f.
The diagram below shows the appearance of the string at t = 0.
P
(a)
Q
Draw the appearance of the string between P and Q at time
(i)
t=
1
4f
P
Q
(1 mark)
(ii)
t=
1
2f
P
Q
(1 mark)
(b)
(c)
The distance between the supports is 1.0 m. A wave in the string travels at a speed of 240 m s-1.
Calculate the frequency of the vibration of the string.
(2 marks)
Now, the frequency is set to double, i.e. 2f, and the distance between the supports is still 1.0 m.
(i) Sketch the appearance of the wave formed on the string below.
(ii) Find the new wavelength of the wave.
(2 marks)
P
Q
9.
A double slit is arranged so that its plane is normal to a beam of laser light, as shown below.
The wavelength of the light is 640 nm. The slit separation in the double slit arrangement is 0.85 mm.
Coherent light emerges from the slits and an interference pattern is observed on a screen. The screen
is parallel to the plane of the double slits. The distance between the slits and the screen is 2.4 m.
(a)
(b)
(i)
State what is meant by coherent light.
(1 mark)
(ii)
Explain how an interference pattern is formed on the screen.
(3 marks)
Calculate the separation of the fringes in the interference pattern on the screen.
(2 marks)
(c)
The interference pattern in (b) consists of a series of alternate bright and dark fringes. The
intensity of the light from one slit is now reduced. Suggest the effect on the appearance of the
fringes.
10.
(a)
(2 marks)
A plane transmission grating with 60 slits per mm and a monochromatic light source of
wavelength 400 nm are used for a grating experiment. Find the maximum number of fringes
that can be observed on the screen.
(4 marks)
(b) In order to show more fringes on the screen, explain whether
(i) a finer or a coarser grating should be used.
(ii) longer wavelength or shorter wavelength of incident light should be used.
(2 marks)
List of data, formulae and relationships
Data
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
R  8.31JK 1mol 1
N A  6.02 10 23 mol 1
g  9.81 ms 2 (Close to the Earth)
G  6.67  1011 Nm2kg 2
c  3.00 108 ms 1
e  1.60  1019 C
me  9.11  1031 kg
 0  8.85  1012 C 2 N 1m2
0  4  107 Hm 1
Rectilinear motion
For uniformly accelerated motion:
v  u  at
s  ut 
1 2
at
2
v 2  u 2  2as
Mathematics
Equation of a straight line
y  mx  c
Arc length
 r
Surface area of cylinder
 2rh  2r 2
Volume of cylinder
Surface area of sphere
 r 2 h
 4r 2
Volume of sphere

For small angles,
4 3
r
3
sin  tan   (in radians)
Astronomy and Space Science
Energy and Energy Use
GMm
U 
r
gravitational potential energy
P  AT 4
Stefan’s law
Q
A(TH  TC )
k
t
d
k
U 
d
1
P  Av 3
2
f
v 
 
f0
c 0
Doppler effect
Atomic World
1
me v m ax2  hf  
2
En  
1
n2
rate of energy transfer by conduction
thermal transmittance U-value
maximum power by wind turbine
Medical Physics
Einstein’s photoelectric equation
 me e 4 
13.6
 2 2    2 eV
n
 8h  0 
energy level equation for hydrogen atom
h
h
 
p mv
de Broglie formula
1.22

d
Rayleigh criterion (resolving power)

1.22
d
Rayleigh criterion (resolving power)
power  1 / f
I
L = 10 log
I0
power of a lens
Intensity level (dB)
Z  c

acoustic impedance
Ir
( Z  Z1 )
 2
I 0 ( Z 2  Z1 ) 2
I  I 0 e  x
medium
2
intensity reflection coefficient
transmitted intensity through a
A1.
E  mc T
A2.
E  l m
A3.
pV  nRT
A4.
pV 
A5.
EK 
energy transfer during heating and
Q1Q2
D1.
F
D2.
E
equation of state for an ideal gas
D3.
E
1
Nmc 2
3
kinetic theory equation
D4.
R
3RT
2N A
molecular kinetic energy
D5.
R  R1  R2
resistors in series
D6.
1
1
1


R R1 R2
resistors in parallel
force
D7.
p  IV  I 2 R
power in a circuit
cooling
energy transfer during change of
state
v p

t t
4 0 r 2
electric field strength due to a point
Q
4 0 r
Coulomb’s law
2
charge
electric field between parallel
V
d
plates (numerically)
l
A
resistance and resistivity
B1.
F m
moment F  d
moment of a force
D8.
F  BQvsin 
force on a moving charge in a
B2.
E p  mgh
gravitational potential energy
D9.
F  BIl sin 
force on a current-carrying
B3.
B4.
EK 
kinetic energy
D10.
B
B5.
P  Fv 
mechanical power
D11.
B
B6.
a
centripetal acceleration
D12.
N
B7.
F
Gm1 m2
r2
Newton’s law of gravitation
D13.
Vs
N
 s
Vp N p
ratio of secondary voltage to
primary voltage in a transformer
C1.
y 
D
a
E1.
N  N 0 e  kt
law of radioactive decay
C2.
d sin  n
E2.
t1 
2
r
1 2
mv
2
W
t
  2r
fringe width in double-slit
interference
diffraction grating equation
2
C3.
1 1 1
 
u v
f
equation for a single lens
magnetic field
conductor in a magnetic field
0 I
2r
magnetic field due to a long
 0 NI
magnetic field inside a long
straight wire
l
solenoid

t
In 2
k
E3.
A  kN
E4.
E  mc 2
induced e.m.f.
half-life and decay constant
activity and the number of
undecayed nuclei
mass-energy relationship