1. WAVES

2. WAVES
waves waves waves waves waves waves waves waves waves waves waves waves waves

3. 1. General Wave Properties
What actually do waves do?
It provides a mechanism for the transfer of energy from one point to another without physical transfer of any materials.

4. Waves are produced if there are any vibrations
There are basically 2 types of waves - transverse and longitudinal.
They differ in their vibration of the particles of the medium

5. Longitudinal waves:

6. Transverse waves:

7. Wave Terminology Amplitude, A:
The maximum displacement of a particle from its rest position

8. Wave length (λ)
The distance between two successive particles which are in same phase and same position
It can also be defined as the distance between two successive crests or troughs for transverse waves
It can also be defined as the distance between two successive compressions or rarefactions for longitudinal waves

9. Crests and Troughs
The upper part of a transverse wave is called as Crest
The lower part of a transverse waves is called as Trough

10. Phase
The direction of movement of a particle when the waves passes is called as Phase

11. Frequency (f)
The number of complete oscillations made by a particle in one second
It can also be defined as the number of waves passed in one second

12. Period (T) The time taken for a particle to complete one oscillation
It can also be defined as the time taken for one complete wave to pass a point

13. Wavefront Any section or part of a wave is called as Wave front
Mostly it is represent with straight lines

14. Question
Figure shows the graph of the variation of the displacement of a wave with distance along the wave at a particular time.

15. State values for (i) the amplitude of the wave = cm
(ii) the wavelength of the wave =

16. State values for (i) the amplitude of the wave = 0.6 cm
(ii) the wavelength of the wave =
5 cm

17. Question
Figure shows the graph of the variation of the displacement of a wave with time at a particular point along the wave.

18. State values for the time for one complete cycle = s
the frequency of the wave = Hz

19. State values for the time for one complete cycle = 1.25 s
the frequency of the wave =
0.8 Hz

20. Note:
Always check the axes of the graph and analyse what you are given. Do not jump to the conclusion that the X-axis is always wavelength for they may give you period.

21. The Wave Equation
Remember that speed can be found from the equation:

22. The Wave Equation For waves, So But λ v = velocity v = T
λ = wavelength (distance) So
v = 1 T
But
f =

23. The Wave Equation
Hence v = fλ

24. Wave Production and Ripple Tank

25. Ripple Tank
The Ripple Tank consists of a shallow glass-bottomed tray, a light source directly above the tray and a white screen below.
Waves formed by a vibrator bobbing up and down.

26. Ripple Tank
Waves formed can be plane waves or circular waves.

27. Ripple Tank
Screen below water tray is used to capture image of waves produced.
The apparatus is used to investigate waves travelling through water.

28. Reflection of Waves

29. Note:
When water waves get reflected, the only thing that changes is the direction.
Wavelength and frequency are the same throughout.

30. Reflection of Waves

31. Reflection of Waves

32. Effect of Water depth on Waves

33. Effect of Water depth on Waves

34. Effect of Water depth on Waves
In moving from deep to shallow water the water,
the waves will move with a slow speed,
the waves’ wavelength will become shorter,
the frequency of the waves will be constant.

35. Refraction of Waves
Refraction of water waves occurs when waves move from deep water to shallow water (or vice versa). As with light it is brought about due to the different speeds of the waves passing through differing media.

36. Refraction of Waves
We have already seen waves entering a region of shallow water will be slowed down.

37. Refraction of Waves
Seen from the side view the change in wavelength can be seen more clearly.

38. Refraction of Waves
In a similar way to light slowing down as it enters a different media this will result in the water waves bending towards the normal as they pass from deep to shallow water.

39. Refraction of Waves Note: Wavelength and speed changes for this case.
The frequency of the waves stays the same.