Do halogen bulbs also contain mercury?
These two types of bulbs are quite different from one another and only fluorescent bulbs contain any mercury. A halogen bulb is a modern variation on the old-fashioned incandescent bulb and uses thermal radiation from a white-hot tungsten filament to produce its light. In contrast, a fluorescent bulb produces light without heat, at least in principle, and begins that process with an electric discharge in mercury vapor. The path to white light in a fluorescent bulb is somewhat complicated. The bulb contains a thin vapor of mercury and other gases and electrons are injected into that vapor by heated metal electrodes at the bulb’s two ends. An electric current is then driven through the mercury vapor, causing the mercury atoms to emit light. But the light they emit is primarily invisible ultraviolet light, a seemingly foolish waste of energy. However, this ultraviolet light never leaves the bulb and instead allows the bulb to emit a carefully tailored spectrum of visible light. The ultrav
