1. Wave Mechanics
Physics 1

2. What is a wave? A wave is: an energy-transferring disturbance
moves through a material medium or a vacuum

3. Categories of Waves Mechanical – require a material medium
Medium – state of matter (solid, liquid, gas, plasma)
Electromagnetic – can move through empty space (vacuum)

4. Types of Waves
In a transverse wave, the displacement of the particles of the medium is perpendicular to the direction of wave motion.

5. Types of Waves
Transverse Wave

6. Types of Waves
In a longitudinal wave, the displacement of the particles of the medium is parallel to the direction of wave motion.

7. Types of Waves
Longitudinal
Transverse l
compression
rarefaction

8. Wave Characteristics frequency ( f ) period ( T ) amplitude (A) phase
wavelength (l)
speed ( v )

9. 1 cycle per second = 1 hertz (Hz)
Wave Characteristics
The frequency (f) of a wave is the number of complete vibrations (cycles) per unit of time.
1 cycle per second = 1 hertz (Hz)

10. Wave Characteristics
The period (T) of a wave is the time for the completion of a cycle. Measured in seconds.

11. Wave Characteristics
The amplitude (A) of a wave is the maximum displacement of the particles in a medium from equilibrium. (“height from rest to crest”)
related to the energy in the wave.
Higher amplitude =
more energy
higher frequency
shorter wavelength

12. Wave Characteristics
The phase of a wave describes the position and direction of any particle in a wave-carrying medium.

13. Wave Characteristics

14. Wave Characteristics
The wavelength (l) of a wave measures the distance between any two consecutive points in-phase.

15. Wave Characteristics v = d = l = l f t T
The speed (v) of a wave depends on the properties of the medium through which it is traveling.
v = d = l = l f
t T

16. Electromagnetic Spectrumf f l l

17. Wave Properties
The direction of propagation of the advancing wave is perpendicular to the wave front. This is due the wave property of rectilinear propagation.

18. Wave Properties
fixed end
free end

19. Wave Properties
When wave encounters a boundary between two media of different propagation speed, some wave energy can be turned back. This is called the wave reflection.

20. Wave Properties
reflected wave
incident wave

21. Refraction - the bending of a wave caused by a change in speed as the wave moves from one medium to another.

22. Wave Properties
When a wave passes through an opening in a barrier, the wave energy will spread out beyond the barrier. This is called the wave diffraction.

24. Wave Properties
Principle of Superposition - When two waves traveling independently through the same medium, the resultant displacement of any particle at a given time is the vector sum of the displacements that the individual waves acting alone would give it.

25. Wave Properties
When two wave pulses encounter each other in a medium, the wave pulses will superpose beyond the barrier. This is called the wave interference.

26. Constructive Interference
Wave Properties
Constructive Interference

27. Destructive Interference
Wave Properties
Destructive Interference

28. Standing Waves
A standing wave is the result of two waves of the same frequency and amplitude traveling in the opposite directions through the same medium.

29. Standing Waves
A point of no disturbance in a standing wave is called a node.
A point in standing wave where the amplitude is maximum is called an antinode.

30. Standing Waves
The fundamental frequency (or natural frequency) of a medium occurs when it vibrates with the simplest standing wave – 2 nodes + 1 antinode.

31. Standing Waves
The harmonic of a wave is a component frequency of the wave that is an integer multiple of the fundamental frequency.
1st Harmonic = 5
2nd Harmonic = 10
3rd Harmonic = 15
4th Harmonic = 20

32. Harmonic Series