An incandescent light bulb is a type of electric light that uses a wire filament heated to a high temperature by an electric current passing through it, causing it to glow with visible light (incandescence). The hot filament is usually protected from oxidation with a glass or quartz envelope. The gas inside the bulb prevents the oxygen in the air from reaching the hot filament, which would otherwise cause it to quickly burn out.
Incandescent bulbs are made in various shapes and sizes, and they produce different amounts of light depending on their size and design. The smaller candelabra bulbs typically used in chandeliers and other decorative fixtures produce about 15 lumens per watt, while larger standard A-shaped bulbs used for general lighting purposes produce around 14 lumens per watt. Some novelty incandescent bulbs can produce up to 100 lumens per watt.
While most incandescent bulbs have a tungsten filament, some types use an alternative material such as carbon or thallium oxide. These alternative materials allow for higher temperatures and greater efficiency, but they also result in more expensive Bulbs.
One advantage of incandescent bulbs over other types of electric lights is that they emit a continuous spectrum of light. This means that all wavelengths of visible light are emitted equally, giving the human eye a full range of colors to perceive. Other lights sources, such as fluorescent lamps and LED lights, emit light at specific wavelengths rather than across the entire spectrum.