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1. WAVES

2. What are Waves?

3. •Try to wave your hand
and
say HELLO to your
seatmate!

4. •Wave is a repetitive disturbance
that travels through a medium or
vacuum and carries energy.

6. Properties of Waves

7. • Frequency
–Number of waves produced per unit
time.
–Its unit is hertz (Hz)

9. • Period
–Time taken for one complete cycle of
the wave to pass a reference point.
–Measured in seconds.

10. Period = 1/ frequency
T= 1 / f

11. EXAMPLE:
The sound wave has a frequency of 50 Hz. What
is the period of the wave?

12. •ANSWER:
=0.02 seconds

13. • Wavelength
–Distance between any two successive
points in a wave that are in phase with
each other.

14. • Speed
–Distance traveled by a wave per unit
time.

15. • Wave speed =
•frequency x wavelength
• Wave speed =
•wavelength / period

16. • EXAMPLE
–Sound wave has a frequency of
10,000 Hz and a wavelength of 1.50
meter in water. What is the speed
of the sound in water?
1.Wave speed = frequency x wavelength
2. Wave speed = wavelength / period

17. •ANSWER:
–15,000 m/s

18. • Amplitude
–Maximum amount of displacement of a
particle on the medium from its resting
position.
–The greater amplitude, the greater the
energy carried by the wave.

19. Classification of Waves

20. Classification of Waves
• According to their movement:
–Transverse wave
–Longitudinal wave
• According to their nature:
–Mechanical wave
–Electromagnetic wave

21. • Transverse wave
–Is one in which the particles of the
medium are vibrating perpendicularly
to the direction of wave propagation.

22. Parts of Transverse Wave

23. • Example of transverse wave:
–Light wave
–Water wave
–Vibrating guitar string
–Ripples from a stone thrown into a
pond

24. • Longitudinal Waves
–Waves in which the medium moves
back and forth in the same direction as
the wave.

25. Parts of Longitudinal wave

26. • Example of Longitudinal wave:
–Sound waves

27. • Mechanical Waves
–Require a medium to propagate

28. • Example of Mechanical Wave:
–Sound wave
–Water wave

29. • Electromagnetic Waves
–Can travel in vacuum and in any
medium.

30. • All electromagnetic waves are
transverse waves.

31. •Speed of electromagnetic
wave in vacuum= 3x10⁸
m/s

32. Electrmagnetic Spectrum

33. Types of Electromagnetic Waves
• Radiowave
• Microwave
• Infrared
• Visible light
• Ultraviolet
• X-ray
• Gamma ray

34. Radiowave
(Heinrich Hertz)
Uses:
- radio communication
- transmit data
- communication
satellites

35. • Other uses include:
–GPD
–Bluetooth
–Wi-Fi

36. Microwave
(James Clerk Maxwell)
• Uses:
–Cook food
–Radar to predict weather
–Garage door openers
–Keyless entry system

37. Infrared
(William Hershel)
• Uses:
–TV remote
–Infrared thermal- imaging cameras

38. Visible light
Color of Light Wavelength
Violet 410 nm
Blue 470 nm
Green 550 nm
Yellow 590 nm
Orange 610 nm
Red 760 nm

39. Ultraviolet
(Johann Wilhelm Ritter)
• A major source of ultraviolet is the
Sun.

40. X-ray
(Wilhelm Conrad Roentgen)
• Penetrate tissue like skin and muscle

41. Gamma ray
(Paul Villard)
• Used in treating cancer
• Used to detect crack in metals

42. Questions

43. 1. Give an example of wave that
you can see around the
classroom/campus.

44. 2. What do you call to the
highest point of the wave?

45. 3. The lowest point of the wave
is called __________.

46. 4. It is the distance between
two successive points in a wave.

47. 5. It is the distance traveled by a
wave per unit time.

48. 6. It is the number of waves
produced per unit time.

49. 7. What is the difference between
transverse and longitudinal wave?

50. 8. What is the difference
between mechanical and
electromagnetic wave?

51. 9. What is the speed of
electromagnetic waves in
vacuum?

52. 10. Who discovered
microwaves?

53. 11. What is the arrangement of
electromagnetic waves in order
of increasing wavelength?

54. 12. What is the arrangement of
electromagnetic waves in order
of increasing energy?

55. 13. Who discovered radio
waves?

56. 14. It is also known as heat
waves.

57. 15. What is the major source of
ultraviolet ray?

58. 16. Bluetooth, Wi-Fi, and GPS
technologies use
________________.

59. 17. Who discovered Gamma
ray?

60. 18. It is the only
electromagnetic wave that is
visible to the unaided eye.

61. 19. What is the arrangement of
the components of white light
in order of increasing
wavelength?

62. 20. Is sound wave mechanical or
electromagnetic?