Fluorescent tubes are long, cylindrical light fixtures that use a gas-filled tube to produce light. Inside the tube, a small amount of mercury vapor and a phosphor coating work together. When electricity passes through the gas, it emits ultraviolet light, which then excites the phosphor coating, creating visible light. These tubes are commonly used in commercial and industrial settings due to their energy efficiency and long lifespan compared to traditional incandescent bulbs. They come in various sizes and color temperatures, making them suitable for different applications, including offices, warehouses, and schools.