The electrons orbiting atoms of the gas inside an electric discharge lamp
are at certain fixed energy levels. The energy level of the orbiting
electrons is raised when the traveling electrons of an arc
collide with them and give up some energy. The orbiting electrons are not
stable at the higher energy level and drop back to their original level.
In doing so each electron gives up a photon of energy which is emitted as
The elements which serve as halogen gases are usually iodine or bromine.
The powder coating in an electric discharge lamp is the phosphor. The most
common chemical used to make white light is calcium halophosphate. Other
colors are produced by a variety of other chemicals.
Tungsten is a metal with a high resistance to the flow of electricity and
a melting temperature of 6120 degrees
Fahrenheit. It is often used in incandescent lamp filaments because its
resistance will cause heat to be generated until it glows white. It can
maintain this glow since its melting temperature is so high.
To return to the Table of Contents click TABLE OF CONTENTS