Which type of lamp utilizes mercury vapor to convert ultraviolet light into visible light?

Mercury vapor lamps operate by using an electrical arc between two electrodes within a sealed tube filled with mercury vapor. When electricity flows through the vapor, it excites the mercury atoms, resulting in the emission of ultraviolet (UV) light. However, this UV light is not visible to the human eye. To convert this UV light into visible light, a phosphor coating is applied to the inside of the lamp. This phosphor absorbs the UV radiation and re-emits it as visible light.

In contrast, incandescent lamps produce light by heating a filament until it glows, using electrical resistance to generate light without needing any gas or vapor. Halogen lamps are a type of incandescent that uses halogen gas to improve efficiency and lifespan. LEDs, or light-emitting diodes, generate light through electroluminescence, using a completely different principle that does not involve mercury or UV light conversion. Understanding the operational mechanism of mercury vapor lamps highlights the distinct way in which they utilize mercury vapor to generate visible light, setting them apart from other types of lighting technologies.