Question

Phosphorus undergoes slow combustion and glows in dark. The process is called:

• A. photochemical change
• B. chemiluminescence
• C. flourescence
• D. phosphorescence

Answer 1

The correct option is D phosphorescence

Phosphorescence is a specific type of photoluminescence related to fluorescence. Unlike fluorescence, a phosphorescent material does not immediately re-emit the radiation it absorbs. The slower time scales of the re-emission are associated with "forbidden" energy state transitions in quantum mechanics. As these transitions occur very slowly in certain materials, absorbed radiation may be re-emitted at a lower intensity for up to several hours after the original excitation.
Commonly seen examples of phosphorescent materials are the glow-in-the-dark toys, paint, and clock dials that glow for some time after being charged with a bright light such as in any normal reading or room light.
phosphorus actually exhibit this property.