1. Electromagnetic Waves

2. Electromagnetic Spectrum

4.  Radio Waves  f ~ 10 6 Hz – 10 9 Hz  λ ~ 300 m – 0.3 m  Lowest frequency, highest wavelength  Used to transfer information (TVs, Radios etc)  Used in astronomy (radio telescopes)

5. Electromagnetic Spectrum  Microwaves  f ~ 10 9 Hz – 10 12 Hz  λ ~ 300 mm – 0.3 mm  Used to carry long distance telephone conversations  Used to cook

6. Electromagnetic Spectrum  Infrared Waves  f ~ 10 12 Hz – 4.3 x 10 14 Hz  λ ~ 0.3 mm – 700 nm  Felt as heat  Remote controls often use infrared ( λ ~1000 nm)

7. Electromagnetic Spectrum  Ultraviolet Light  f ~ 7.5 x 10 14 Hz - 10 17 Hz  λ ~ 400 nm – 3 nm  Causes suntans and sunburns (and cancer)  Majority of UV rays are absorbed by Ozone (O 3 )

8. Electromagnetic Spectrum  X-Rays  f ~ 10 17 Hz - 10 20 Hz  λ ~ 3 nm – 0.003 nm  Used in medicine

9. Electromagnetic Spectrum  Gamma Rays  f ~ 10 20 Hz and higher  λ ~ 0.003 nm and lower  Can kill cancer cells and microorganisms in food