Technology / Radar / Phosphorescence: Emission of light without sensible heat, particularly as a result of but continuing after absorption of radiation from some other source. An example is the glowing of the screen of a cathode-ray tube after the beam of electrons has moved to another part of the screen. It is this property that results in the chart like picture which gives the ppi its principal value. Persistence is the length of time during which phosphorescence takes place. The emission of light or other radiant energy as a result of and only during absorption of radiation from some other source is called fluorescence.
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