PRODUCING LIGHT
Incandescent Lights Heating a piece of metal until it glows Thin wire called a filament More than 80 percent of the energy in
this light is produced as heat
Fluorescent Lights Filled with a gas at low pressure Inside of bulb is coated with
photophosphors that emit visible light when the absorb ultraviolet radiation.
Contains electrodes at each end Very efficient
Neon Lights Vivid glowing colors Glass tube filled with different gases to
make different colors Molecules collide to make the light
Sodium Vapor Lights Tube that contains neon gas and argon
gas and a small amount of sodium metal Use in street lights Emits a yellow glow
Tungsten-Halogen lights Tungsten filament inside quartz bulb or
tube and a gas Filament becomes hotter than the
incandescent light because of the gas
Lasers Number of light waves are emitted at the
same time. Each atom must give the same energy Light waves are sent from the atoms Helium laser--red light
Laser light is coherent all traveling the same wavelength
Using Lasers CD players Surgincal tools Surveyors for buildings Measure the moons orbit Communications
In Medicine Used to remove cataracts, reshape the
cornea and repair the retina Laser seals off blood vessels as it cuts
and reduces bleeding and scars
CD Player Lasers are used to burn the holes into the
CD so that it can play. Laser is used to read the CD and play
what is on it.
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