Fluorescent light bulbs are a type of energy-efficient lighting that uses an electric current to excite a gas, typically mercury vapor, inside a glass tube coated with phosphors. When the gas is excited, it emits ultraviolet (UV) light, which is then converted into visible light by the phosphors. Fluorescent bulbs are commonly used in commercial and industrial settings such as offices, schools, and hospitals because they are more energy efficient and have a longer lifespan than traditional incandescent light bulbs. They also come in different sizes and shapes, such as linear tubes or circular bulbs, and can be used in various fixtures such as ceiling lights, lamps, and under-cabinet lights. They also come in different colors and temperature, like cool white, daylight, and warm white. However, they contain a small amount of mercury and thus are considered hazardous waste and should be disposed of properly.