1. Waves

3. What are waves?
A wave is a phenomenon in which energy is transferred through vibration.

4. Types of Waves
Transverse Waves
Longitudinal Waves

5. Transverse Waves
are waves which travel in a direction perpendicular to the direction of vibrations.
Direction of vibrations
Direction of wave

6. Generating Transverse Waves

7. Transverse Waves examples include water waves rope waves light wave
electromagnetic waves

8. Longitudinal Waves sound waves
are waves which travel in a direction parallel to the direction of vibrations.
Direction of vibration
Direction of wave
examples include
sound waves

9. Generating of Longitudinal Waves [slinky spring]

10. Characteristics of A Wave
Crests and Troughs
Amplitude
Wavelength
Frequency
Period
Speed

11. Crests and Trough Crests are high point of a wave
Troughs are low point of a wave
displacement
crest
distance
trough

12. Amplitude (A)
is the height of a crest or depth of a trough measured from the normal undisturbed positions.
displacement
distance
crest
trough
Amplitude
Amplitude

13. SI Unit For Amplitude is measured in metres (m) crest trough
displacement
distance
crest
trough
Amplitude
Amplitude

14. Wavelength ()
is the distance between two successive crests or troughs
displacement
distance
Amplitude
crest
trough
Wavelength
Wavelength

15. SI Unit For Wavelength is measured in metres (m) Wavelength crest
displacement
distance
Amplitude
crest
trough
Wavelength

16. Frequency (f)
is the number of vibrations in one second.

17. SI Unit For Frequency is the Hertz (Hz)
1 Hz is 1 vibration in 1 second.
50 Hz is 50 vibrations in 1 second.

18. Test Yourselves Explain the meaning of 28 Hz, 100 Hz , 135 Hz,

19. Period (T)
is the time taken for one complete vibration. (or oscillation or cycle)

20. SI Unit For Period
is measured in second (s)

21. Relationship between Period (T) and Frequency (f)
f = 100 Hz  T = 1/100 s
f = 40 Hz  T = 1/40 s
f = 23 Hz  T = 1/23 s
f = Hz  T = 1/8 s
f = f Hz  T = 1/f s

22. Relationship Between f and T

23. Speed Of a Wave
is the distance moved in one second.

24. SI Unit For Speed
is measured in metre per second (ms-1or m/s)

25. V = f Wave Equation Speed of a wave = wavelength  period
= wavelength x frequency
where v = speed, f = frequency and
 = wavelength
V = f

26. Describing Waves Displacement-Time Graph for one particle on the wave

27. GCE O-Level
Past Examination Paper
Science (Physics)

28. B Nov 1991 9. The diagram shows the outline of a water wave.
What are the values of the amplitude and the wavelength?
amplitude / cm wavelength / cm A B C D B

29. C GCE O Nov 1994 11. Which wave is longitudinal ? A light B radio
C sound
D water C

30. O’ level Physics
Nov 1995
11. The speed of 100 Hz wave was measured on four
different days. The results are shown in the table.
On which day the wave have the longest
wavelength ?
day speed of wave
A ms-1
B ms-1
C ms-1
D ms-1 D

31. C GCE O Nov 1996 9. A source vibrates at frequency of 20 Hz and
produces waves of wavelength 0.02 m.
At which speed do these waves travel out from
the source ?
A ms-1
B ms-1
C ms-1
D ms-1
Hint:
v = f C

32. Nov 1998
9. A VHF radio station broadcasts at a frequency of 60MHz (6.0 x 107 Hz). The speed of radio waves is 3.0 x 108ms-1.
What is the wavelength of the waves broadcast by the station?
A 0.2 m
B 0.5 m
C 2.0 m
D 5.0 m
Hint:
v = f D

33. Nov 1998
5. The diagram shows a coil spring along which a longitudinal wave is moving.
(a) Mark on the diagram a distance equal to the
wave length of the wave [1]
(b) Label on the diagram with the letter C where
the coils of the spring are compressed [1] C C C
Wave length
(continue in next slide)

34. (c) Is the wave on the spring more like a sound wave
(Cont. …) Q 5
Nov 1998
(c) Is the wave on the spring more like a sound wave
or a light wave? [1]
Sound wave, because sound wave is a longitudinal
wave but light wave is a transverse wave..

35. 5. The diagram below shows a transverse wave travelling a rope.
Nov 1997
5. The diagram below shows a transverse wave travelling a rope.
wavelength
amplitude
(a) Mark on the diagram which is equal to (i) the wavelength, (ii) the amplitude of the wave. Label your answers [2]
(b) If the wavelength is 0.8m and the frequency is 2 Hz, what is the speed at which the wave moves along the rope ? [2]
v = f = 0.8 x 2 = 1.6 ms-1

36. Nov 1996
6(a) Explain the difference between a transverse and a longitudinal wave [2]
Transverse wave is a wave that its direction of
vibration is perpendicular to the direction of
propagation. It can travel through vacuum.
Longitudinal wave is a wave that its direction of
vibration is parallel to the direction of
propagation. It needs medium to travel.
(b) State one example of each type of wave.
Transverse
Longitudinal [2]
Light
Sound

37. 9.(a) Explain the difference between transverse and
GCE ‘O’ LEVEL Nov 1995
9.(a) Explain the difference between transverse and
longitudinal waves, referring in your answer to
the direction in which the waves travel [2]
Transverse waves are waves that their direction
of vibration is perpendicular to their direction
of propagation.
Longitudinal waves are waves that their
direction of vibration is parallel to their
direction of propagation.
(continue on next slide)

38. (Cont. …) Q Nov 1995
9.(b) The speed of sound in water is 1500m/s. What is a
wave length of a sound wave of frequency 250Hz
travelling through water ? [2]
Since v = f
therefore =  250
 = 1500 / 250 = 6.0 m

39. 6. The diagram shows the air pressure at different
Nov 1993
6. The diagram shows the air pressure at different
distances from a loudspeaker.
wavelength
amplitude
(a) Mark carefully on the diagram: [2]
(i) a distance which is the wavelength of the
sound wave;
(ii) the amplitude of the sound waves.
(continue on next slide)

40. (Cont. …) Q Nov 1993
6(b) If the wavelength of a sound wave of frequency
250 Hz is 1.4 m, calculate the speed of the wave.
[2]
since v = f
therefore, = 1.4 x 250
= 350 ms-1

41. 5.(a) With the aid of a diagram, explain what is meant
by the frequency and wavelength of a wave. [5]
Frequency is the
number of vibrations
per second.
Wavelength is the distance from a point on a
wave to its next corresponding point.
It usually denote as .. 
(b) What is a longitudinal wave ? [2]
Longitudinal wave is a wave that its direction
of vibration always parallel to the direction of
propagation.
(continue in next slide)