1. Electromagnetic Spectrum
5/14/15

2. Types of Waves
Electromagnetic Waves: a wave that consists of oscillating electric and magnetic fields
Mechanical Waves: A wave that requires a medium through which to travel

3. Electromagnetic Spectrum
Electromagnetic Spectrum: electromagnetic waves that range in wavelength and frequency

4. Electromagnetism Abb.
EM or E&M = Anything Electromagnetic

5. Electromagnetic Waves
Travel at the speed of light
Are transverse waves
Are produced by accelerating charges
Can propagate without a medium
Transfer energy
Photons transfer energy at different frequencies
Have perpendicular electric and magnetic fields to propagation

6. EM Waves vs. Mechanical Waves
Travel at the speed of light
No Medium needed
Transfer energy by photons
Transverse waves only
Mechanical Waves
Travel much slower then EM Waves
Needs a medium to propagate
Transfer energy through the medium
Can be transverse or longitudinal waves

7. Electromagnetic Waves

8. Electromagnetic Waves

9. Electromagnetic Spectrum

10. The Electromagnetic Spectrum
Long wavelengths, low frequencies and energy
Short wavelengths, high frequencies and energy
Radio Waves
Microwaves
Infrared
Visible Light
Ultraviolet
X-Rays
Gamma Rays

11. Electromagnetic Spectrum in Astronomy

12. The Electromagnetic Spectrum
Radio Waves (greater then 0.1 m)
communications, TV, radio stations

13. Galactic Center
Radio Continuum (0.402 GHz)
Wavelength = 1 m

14. Galactic Center
Atomic Hydrogen 1.4 GHz
Wavelength = 0.2 m

15. Galactic Center
Radio Continuum ( GHz)
Wavelength = 0.12 m

16. Combined radio image from the Very Large Array and Green Bank Telescope
Wavelength = 0.90 m

17. The Electromagnetic Spectrum
Microwaves (0.3 m to m)
radar, cell phones, heating food (microwave oven)

18. Electromagnetic Spectrum

19. Galactic Center
Molecular Hydrogen (115 GHz)
Wavelength = m

20. Plank telescope
Wavelength = .350 to 10 mm

21. The Electromagnetic Spectrum
Infrared (0.001 m to 7×10-7 m)
heat, photography, night vision goggles

22. Galactic Center
Infrared (3-25 × 103 GHz)
Wavelength = 2 × 10-5 m

23. Galactic Center
Near Infrared (25 × 103 GHz)
Wavelength = 1.2 × 10-5 m

25. The Electromagnetic Spectrum
Visible light
7×10-7 m (red) to 4×10-7 m (violet)
Human eye sight

26. Galactic Center
Optical (460 × 103 GHz)
Wavelength = 6.5 × 10-7 m

29. Infrared vs. Visible Light

30. The Electromagnetic Spectrum
Ultraviolet (4×10-7 m to 6×10-8 m)
Sunburns, purifying water

31. Galactic Center
Ultraviolet (14 x 106 GHz)
Wavelength = 2 x 10-8 m

32. The Electromagnetic Spectrum
X rays (6×10-8 m to 10–13 m)
medicine, astronomy, security screening

33. Galactic Center
X-Ray ( × 106 GHz)
Wavelength = 2 × 10-9 m

34. Chandra (X-Ray)

35. The Electromagnetic Spectrum
Gamma Rays (less than 10–13 m)
cancer treatment, astronomy

36. Galactic Center
Gamma Ray (2.4 × 1013 GHz)
Wavelength = 1.25 × m

37. Fermi (Gamma Rays)

39. The Sun at Different Wavelengths of Radiation

40. Notes Quiz on Monday
You can use any handwritten notes that you have taken from for this semester (from Jan.)
All notes are on my webpage: