230 likes | 388 Views
Sunlight. Plasma at extremely high temperatures. 6,000 ºC Outer 1.5x10 7 ºC Inner. [http://www.astronomy.com/asy/objects/images/sun_full_disk_soho_09_14_1997.jpg]. Rather uniform spectrum of colors. [http://www.videoessentials.com/images/res_spectral12.gif]. Incandescent Light.
E N D
Sunlight • Plasma at extremely high temperatures. • 6,000 ºC Outer • 1.5x107 ºC Inner [http://www.astronomy.com/asy/objects/images/sun_full_disk_soho_09_14_1997.jpg]
Rather uniform spectrum of colors [http://www.videoessentials.com/images/res_spectral12.gif]
Incandescent Light • These heat a piece of metal until it produces light. • The thin piece of metal is called a filament.
Mainly red/orange/yellow in spectrum of incandescent lights [http://www.videoessentials.com/images/res_spectral12.gif]
Incandescent Light • About 80% of the energy used is converted to heat (infrared).
Fluorescent Lights • A glass tube is covered with phosphors that give off light when UV rays from the gas inside are given off.
Mainly blue/green in spectrum of fluorescent lights [http://www.videoessentials.com/images/res_spectral12.gif]
Fluorescent Lights • Uses one-fifth the energy of an incandescent light bulb. • Can contain mercury so must be recycled after use.
Neon Lights • Electricity is passed through a glass tube filled with gas, and the particles collide and give off light.
This creates an emission spectrum of “lines” at certain colors [http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/modpic/neoncomp.jpg]
Lasers • Atoms of a gas are charged with energy and they in turn all give off light with the same wavelength.
Lasers • Used in medicine and in reading optical data (CD’s, DVD’s)
Tungsten-Halogen Lights • The filament is made of the Tungsten which can create a tremendous amount of heat, and light. [http://www.daviddarling.info/images/tungsten_halogen_lamp.jpg]
Has a rather uniform spectrum and is somewhat energy efficient. [http://www.molecularexpressions.com/primer/lightandcolor/images/lightsourcesfigure3.jpg]
Sodium-Vapor Lamps • Sodium metal becomes very hot and changes to a vapor to produce yellow-orange light. [http://upload.wikimedia.org/wikipedia/en/6/63/Na-lamp-2.jpg]
Can be used outdoors to reduce light pollution at night. [http://www.sao.arizona.edu/FLWO/LIGHT/MontePatria2.jpg]
Uses of Light • Polarizing Filters • Only light waves that are vibrating in one direction pass through. • Used in sunglasses to block “glare”
Uses of Light • Optical Fibers • Light waves pass through a glass tube for communication purposes. • Telephone, TV, Internet
Total Internal Reflection allows the light waves to “travel” through the tube. Click here for a demonstration