Fluorescence

Fluorescence is a process where certain materials absorb light at one wavelength (usually ultraviolet or blue) and then promptly emit it at a longer, visible wavelength. When these substances are exposed to specific light sources, they glow temporarily. This effect occurs because the absorbed energy excites electrons in the material; as they return to their normal state, they release excess energy as visible light. Fluorescence is commonly observed in items like highlighter ink, certain minerals, and biological tissues under UV light, and is widely used in scientific, medical, and industrial applications for detection and analysis.