1. The Electromagnetic Spectrum Part 1
Chapter 4
The Electromagnetic Spectrum
Part 1

2. Visible Light
Part of the Electromagnetic Spectrum

4. All types of electromagnetic energy move in waves.
Light and sound move by waves.
Light moves at
3 x 108 m/s
Sound moves at
340 m/s
1 mile = 1609 m

5. All types of electromagnetic energy move in waves.
Light moves at
3 x 108 m/s
Sound moves at
340 m/s
Is sound a form of electromagnetic radiation?

6. Electromagnetic Waves
Properties of waves include speed, frequency and wavelength
All electromagnetic waves including light travel at a speed of 3 x 108 m/s.

7. Wavelength ()
Measured in units of length: m, nm, A

8. Frequency ()
Measured in cycles/second = hertz (Hz)

10. Visible Light

11. Why do we want to understand electromagnetic radiation (light)?
Well, for one thing, it may someday allow us to become invisible.

12. Electromagnetic Radiation
For all waves  •  = c
c = the speed of light = 3.00 x 108 m/s

13. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?

14. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?
665 nm = 665 x 10-9 m

15. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?
665 nm = 665 x 10-9 m
c =  • 

16. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m

17. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz

18. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the frequency of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz
 = 4.51 x 1014/s or Hz

19. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?

20. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?
7.25 x 1020 Hz = 7.25 x 1020/s

21. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?
7.25 x 1020 Hz = 7.25 x 1020/s
c =  • 

22. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?
7.25 x 1020 Hz = 7.25 x 1020/s
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 7.25 x 1020/s

23. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?
7.25 x 1020 Hz = 7.25 x 1020/s
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 7.25 x 1020/s
 = x m

24. An x-ray has a frequency of 7.25 x 1020 Hz. What is the wavelength?
7.25 x 1020 Hz = 7.25 x 1020/s
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 7.25 x 1020/s
 = x m
 = 4.14 x m

25. Energy of Electromagnetic Radiation
For all waves: E = h • 
h = 6.63 x J • s or J/Hz

26. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the energy of this light?

27. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the energy of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz
 = 4.51 x 1014/s or Hz

28. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the energy of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz
 = 4.51 x 1014/s or Hz
E = h •  = (6.63 x J • s)(4.51 x 1014/s)

29. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the energy of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz
 = 4.51 x 1014/s or Hz
E = h •  = (6.63 x J • s)(4.51 x 1014/s)
E = x J

30. A photon of red light has a wavelength of 665 nm
A photon of red light has a wavelength of 665 nm. What is the energy of this light?
665 nm = 665 x 10-9 m
c =  • 
 = c ÷  = 3.00 x 108 m/s ÷ 665 x 10-9 m
 = x 1014/s or Hz
 = 4.51 x 1014/s or Hz
E = h •  = (6.63 x J • s)(4.51 x 1014/s)
E = x J = 2.99 x J

31. An x-ray has a frequency of 7.25 x 1020 Hz. What is its energy?

32. An x-ray has a frequency of 7.25 x 1020 Hz. What is it’s energy?
E = h •  = (6.63 x J/Hz)(7.25 x 1020Hz)

33. An x-ray has a frequency of 7.25 x 1020 Hz. What is it’s energy?
E = h •  = (6.63 x J/Hz)(7.25 x 1020Hz)
E = x J

34. An x-ray has a frequency of 7.25 x 1020 Hz. What is it’s energy?
E = h •  = (6.63 x J/Hz)(7.25 x 1020Hz)
E = x J
E = 4.81 x J

35. wavelength, frequency and energy
Red Light
 = 665 x 10-9 m
 = 4.51 x 1014 Hz
E = 2.99 x J
 = 4.14 x m
 = 7.25 x 1020 Hz
E = 4.81 x J
X-ray

36. Wavelength, frequency and energy
Wavelength and frequency have an inverse relationship.
Energy and frequency have a direct relationship.
Electromagnetic radiation with a shorter wavelength will have a higher frequency and higher energy.
Electromagnetic radiation with a longer wavelength will have a lower frequency and lower energy.