When an electron returns to its ground state, energy will be released as heat or as an emission of light, known as

A) fluorescence.
B) UV radiation.
C) action spectrum.
D) photoelectron hydrolysis.
E) photoelectron degradation.

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. This process occurs when an electron returns to its ground state from an excited state, releasing energy in the form of light.