What process involves light being emitted due to exposure to ultraviolet (UV) light?

Fluorescence is the process in which a substance absorbs ultraviolet (UV) light and then re-emits light, typically within the visible spectrum. This occurs almost instantaneously, meaning that the emitted light stops almost immediately after the UV light source is removed. The energy from the UV light excites the electrons in the atoms or molecules of the fluorescent material, and as they return to their ground state, they release energy in the form of visible light. This principle is widely used in various applications, including fluorescent lamps and highlighter markers.

In contrast, phosphorescence also involves the absorption of light but differs in the timescale of emission. In phosphorescent materials, the emitted light persists long after the excitation source is removed, as the electrons are trapped in a higher energy state before returning to their ground state much more slowly. Incandescence, on the other hand, is the emission of light due to heat, where objects glow due to being heated, rather than from exposure to light. Bioluminescence refers to light produced by living organisms through chemical reactions, independent of UV light exposure. Thus, fluorescence is specifically the phenomenon that results from the absorption of UV light and subsequent immediate emission of light.