Light‐emitting diodes

Most cities in the united states are in the process

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Unformatted text preview: ities in the United States are in the process of replacing their incandescent traffic lights with LED units because of three big advantages: 1) LEDS are brighter; 2) they last for years; 3) LEDs save a lot of money. If an LED traffic light emits a 182 kJ/mol of energy, to what wavelength, frequency and color of light does this correspond? 1.82 x 105 J x 1 mol = (6.626 x 10‐34 Js)( 3.00 x 108 m/s) 1 mol 6.02 x 1023 λ λ = 6.58 x 10‐7 m x 109 nm = 658 nm is in the red spectrum 1 m (6.58 x 10‐7 m) = 3.00 x 108 m/s = 4.56 x 1014 Hz 2. Label each transmis...
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This note was uploaded on 10/07/2013 for the course C 117 taught by Professor Dragnea during the Spring '09 term at Indiana.

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