1. الفيزياء
د/هالة مصطفى احمد

2. CHAPTER (2)
WAVE MOTION

3. WAVE MOTION 1: Definition.
A wave is a disturbance that propagates through space and time, usually with transference of energy

4. Types of Waves Motion 1-Mechanical waves optics
2-Electromagnetic waves optics
3-Matter waves optics

5. 1-Mechanical waves optics
Mechanical wave optics require a material medium to travel
(air, water, ropes).

6. 1-Mechanical waves optics
These waves are divided into three different types.
1-Transverse waves the medium to move perpendicular to the direction of the wave.
2-Longitudinal waves the medium to move parallel to the direction of the wave.
3-Surface waves are both transverse waves and longitudinal waves mixed in one medium

7. 2-Electromagnetic waves optics
Electromagnetic waves optics do not require a medium to travel (light, radio).

8. 3-Matter waves optics 3-Matter waves optics
Matter waves optics are produced by electrons and particles.

9. Measuring Waves optics
1-Periodic Time
The time taken by the vibrating body to complete one vibration.
2-Frequency
It is the number of complete vibrations per second, in hertz (Hz) f = 1 / T
3- Wavelength
Wavelength (λ) is the length of one complete cycle, in m or cm.

10. Measuring Waves optics
4-Velocity
By knowing the frequency of a wave and its wavelength, we can find its velocity.
v = f λ

11. Measuring Waves optics
5-Amplitude
The amplitude is maximum displacement of vibrating body

12. Moving from one medium to another
Once a wave (incident wave) has reached the end of a medium
Part of the energy is transferred to the medium that is immediately next to it (transmitted wave)
Part is reflected backward (reflected wave).
The energy transferred depends on the difference between the mediums.

13. Collision of waves 1:Constructive interference
2:Destructive interference

14. 1:Constructive interference
It is when the amplitudes of the initial waves are in the same direction.
The resulting wave will be larger than the original waves.
The highest point of a constructive interference is called an anti node.

15. 2:Destructive interference
It is when the amplitudes of the initial waves are opposite.
The amplitude of the resulting wave will be zero.
The point in destructive interference is called a node

16. CHAPTER
(3)
SPECTROSCOPY

17. Spectroscopy Spectroscopy.
Spectroscopy was the study of the interaction between radiation and matter as a function of wavelength.

18. Classification of methods.
2-1:Nature of excitation measured.
1-Electromagnetic spectroscopy
interactions of matter with electromagnetic radiation, such as light.
2-Electron spectroscopy
interactions with electron beams.

19. 3-Dielectric spectroscopy
involves the frequency of an external electrical field
4-Mechanical spectroscopy
involves the frequency of an external mechanical stress.

20. Measurement process
1-Absorption spectroscopy uses the range of the electromagnetic spectra in a substance absorbs.
This includes atomic absorption spectroscopy
( infrared spectroscopy)

21. 2-Emission spectroscopy uses the range of electromagnetic spectra in a substance radiates (emits). The substance first must absorb energy. (spectro fluorimetry)

22. 3-Scattering spectroscopy measures the amount of light that a substance scatters at certain wavelengths, incident angles, and polarization angles. The scattering process is much faster than the absorption/emission process.
(Raman spectroscopy)

23. Story problems
1-A radio wave has a frequency of 83.8 MHz (83.8 x 106 Hz).
What is its period?

24. Story problems
f =83.8 x 106 Hz f = 1 / T T = 1 / f T = 1 / 83.8 x 106 Hz T = 1.1 x 106 s

25. Story problems
2-The light wave velocity in space is 3 x 105 Km/s given that the wavelength of light is 5000Aº.
Find the frequency of light?

26. Story problems V = 3 x 105 Km/s = 3 x 105 x 103 = 3 x 108 m/s
λ = 5000Aº = 5000 x 10-10
= 5000 x 10-7 m
v = f λ
f = v/ λ = 3 x 108 m/s / 5000 x 10-7 m = 6 x 1014 Hz.

27. Story problems
3-The velocity of a wave is 420 m/s. If the frequency of the wave is 85 Hz,
what is its wavelength?

28. Story problems V = 420 m/s f = 85 Hz v = f λ λ = v/f = 420 m/s / 85 Hz

29. Story problems
4-If a wave with a wavelength of 5.0 m has a 3.0 x 10-3 s period,
a. what is its frequency?
b. what is its velocity?

30. Story problems T = 3.0 x 10-3 s λ = 5 m f=? f = 1 / T
f = 1 / 3 x 10-3 s
f = x Hz
v = f λ
v = f λ = 3 x Hz X 5 m
V = 15 x m/sec

31. 5)What are the types of excitation measured of spectroscopy?

32. 6)What are the types of Waves Optics?
7)What are the factors effects on measuring waves optics?

33. 8)Deine each of the following:
1-Spectroscopy

34. Read and mark ( √ )the correct answer:
1-Which type of electromagnetic waves has the greatest:
a-Radio waves
b-Visible light
c-X-rays

35. 2-Which of the following is not an electromagnetic waves:
a-Sound
b-Radio
c-Light

36. 3-light waves are :
a-Transverse waves
b-Longitudinal waves
c-rotating waves

37. 10) Compare between: 1)Electromagnetic spectroscopy
and Electron spectroscopy
2)Constructive and Destructive collision

38. 1)Electromagnetic spectroscopy and Electron spectroscopy
Interactions with electron beams
Interactions of matter with electromagnetic radiation
Interactions
kinetic energy
Intensity of energy
No kinetic energy
Measurement

39. 2)Constructive and Destructive collision
Items
opposites
Same direction
Amplitude
zero
large
Resulting Waves
anode
Anti node
The point interference

40. THANK YOU