While low pressure sodium vapor lamps are the most energy efficient light sources commonly available, producing a pure orange-yellow light with a wavelength of 590 nanometers, high pressure sodium vapor lamps produce a richer spectrum of light that is more pleasing to the eye. One effect that contributes to this richer spectrum is

Question

Quizplus · Accepted Answer

Radiation trapping occurs when light, such as the 590 nanometer light produced by sodium vapor lamps, has difficulty escaping from the lamp due to repeated absorption and re-emission by the gas atoms. This effect contributes to the richer spectrum of high pressure sodium vapor lamps by allowing more time for the light to interact with the gas and potentially undergo processes that broaden the spectrum.

While Low Pressure Sodium Vapor Lamps Are the Most Energy