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Unformatted text preview: frequency modulation (FM).
Microwaves (a few millimeters long) are also used in communications.
Microwave ovens are great for heating food since food is primarily water,
and microwaves have just the right frequency to get water molecules
Infrared (micrometers in length) are used in remote controls to change the
channel, and they are also radiated by objects that are warmer than their
surrounding (like your body). They make night vision equipment possible.
Ultraviolet light is harmful to our bodies because its wavelength is so
small. Short wavelength mean high energy for photons. UV causes our
skin to tan and burn. Fortunately, the ozone layer blocks most UV
radiation, but prolonged exposure to the sun should be avoided, since UV
rays can cause skin cancer. On the positive side UV radiation helps
people to produce their own vitamin D. Electromagnetic Spectrum (cont.)
X-rays are even more energetic, and hence more dangerous, than UV
rays, but luckily they cannot penetrate our ozone layer. They are
produced in space and of course are used by doctors to get pictures of
Gamma rays are the most energetic of the light w...
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This note was uploaded on 11/17/2011 for the course PHYS 121 taught by Professor Burgeson during the Fall '11 term at BYU.
- Fall '11