1. Waves

2. What is a Wave?
"A wave can be described as a disturbance that travels through a medium from one location to another location ."

3. Transverse Wave Motion
A group of people jumps up and sits back down, some nearby people see them and they jump up, some people further away follow suit and pretty soon you have a wave travelling around the stadium. The wave is the disturbance (people jumping up and sitting back down), and it travels around the stadium. However, none of the individual people the stadium are carried around with the wave as it travels - they all remain at their seats

4. Transverse wave
In a transverse wave the particle displacement is perpendicular to the direction of wave propagation
The particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by .
Light waves are transverse in nature.

5. Transverse wave Transverse waves on a string
The string is displaced up and down as the wave travels from left to right, but the string itself does not experience any net motion.

6. RIGHT ANGLES TO WAVE DIRECTION
TRANSVERSE WAVE
vibrations
WAVE DIRECTION
VIBRATIONS ARE AT 90O OR
RIGHT ANGLES TO WAVE DIRECTION

7. longitudinal wave
In a longitudinal wave the particle displacement is parallel to the direction of wave propagation The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions. Pick a single particle and watch its motion
Sound waves are longitudinal

8. VIBRATIONS ARE PARALLEL
LONGITUDINAL WAVE
vibrations
WAVE DIRECTION
VIBRATIONS ARE PARALLEL
TO WAVE DIRECTION

9. Parts of a wave
The crest of a wave is the point on the medium which exhibits the maximum amount of positive or upwards displacement from the rest position
The trough of a wave is the point on the medium which exhibits the maximum amount of negative or downwards displacement from the rest position.

10. Amplitude
The amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position.

11. Wavelength
The wavelength of a wave is the distance between any two adjacent corresponding locations on the wave train.
This distance is usually measured in one of three ways:
crest to next crest,
trough to next trough,
or from the start of a wave cycle to the next starting point.

12. All waves are caused by vibrations
Diagram of a wave
All waves are caused by vibrations
PEAK OR CREST
WAVELENGTH
AMPLITUDE
TROUGH
WAVELENGTH

13. Frequency and Time period
The frequency (f) of a wave is the number of cycles that pass the observer in a given time.
Hertz is the unit of frequency.
Frequency and period are exact inverses of each other,
       f = 1 / T or T = 1 / f

14. Finding the relationship between WAVESPEED, FREQUENCY & WAVELENGTH
10m
Frequency =
4Hz
What is the relationship?
Wavelength =
5 m
Wavespeed =
20 m/s

15. WS F x WL WS = F x WL F = WS WL WL = WS F
wave speed (m/s) = frequency (Hz) x wavelength (m)
WS = F x WL
F = WS WL
WL = WS F WS F x WL

16. Wave Equation
The relation between the speed (v) of a wave ,its wavelength (λ) and frequency (f) is given by
Speed = Wavelength x Frequency
Using the symbols v, λ , and f, the equation can be rewritten as
v = f x λ

17. 1. If the speed of a wave is 340m/s, and its wavelength is 20m, what is its frequency?
wave speed = frequency x wavelength
340 = frequency x 20
frequency = = 17 Hz 20

18. If 300 cycles are produced in 60s and the wavelength is 10m, find:-
(a) the frequency
300 cycles
60s
(b) the wave speed
wave speed = frequency x wavelength
= 5 cycles/s
= 5 Hz
= 5 x 10
= 50 m/s

19. Light waves travel at 300 000 000 m/s
Light waves travel at m/s. If their frequency is 500Hz, find their wavelength
wave speed = frequency x wavelength
= x wavelength =
500 m

20. If 25 cycles occur in 1 second and their wavelength is 3 metres, find the wave speed
wave speed = frequency x wavelength
= x 3
= m/s

21. WAVEFRONTS PEAK/CREST WAVELENGTH
WAVEFRONTS (PEAK/CREST OF WAVES FROM ABOVE)

22. Each line is a peak/crest of a circular wave
Circular Wavefronts
Each line is a peak/crest of a circular wave

25. Diffraction of Waves
Diffraction means spreading out. This can occur to waves when they go through a small gap.

26. Peaks or Crests of Waves
Diffraction (spreading out) of waves through a gap equal or smaller than the wavelength
Spreading out
Peaks or Crests of Waves

27. Small amount of spreading out Peaks or Crests of Waves
Diffraction (spreading out) of waves through a gap larger than the wavelength
Small amount of spreading out
Peaks or Crests of Waves

28. CONSTRUCTIVE
INTERFERENCE
Wave A
Wave B
Output

29. INTERFERENCE
DESTRUCTIVE
Wave A
Wave B
Output

30. Interference of Waves
Wave A
Wave B
Resultant
Wave

31. Constructive Interference
Interference of overlapping waves
Peak meets Peak or
Trough meets Trough
Constructive Interference

32. Destructive Interference
Interference of overlapping waves
Peak meets Trough
Destructive Interference

33. Hope you enjoyed Learning