Incandescent light is a form of electric illumination that uses extreme heat to produce artificial light. This type of light bulb has been widely used for over a century to light homes and entire cities. There are different types of incandescent light, and each differs in the amount of energy required and the radiance emitted.
A standard incandescent light bulb has a number of different components that make it work. When the power switch in a room is turned on, an electric current flows inside the bulb and runs through the thin wire filament inside. This filament is often made of tungsten, which is a metal resistant to high temperatures that produces bright illumination. The filament is usually covered by a thin glass bulb that keeps oxygen outside and protects the tungsten.
Tungsten halogen lamps are a type of incandescent light bulbs that often use less energy, but provide more light. These are made with a special glass that retains the heat that might be lost in standard bulbs. This allows the tungsten to use less power when heating up, and usually gives the lamp a longer life span. One drawback of halogen bulbs is that they are often more expensive than standard ones.
Reflector lights are commonly used in show business, such as on theater stages or by film studios. These bulbs are easily moved, or directed, and can shine light on specific areas. Spotlights are often used for highlighting an exact spot on the stage, while floodlighting and downlighting produce lights of different intensities and sizes to fill space. These lights can be used both indoors and outdoors.
Incandescent light can also include heat lamps, which require a lot of energy and are commonly used as a heat source. These lights are often installed at farms to keep the animals warm during winter. Farmers typically put them in chicken coops or houses where they encourage the birds to lay more eggs.
There are other types of modifications that can be made to incandescent light for specific purposes. Lamp manufacturers sometimes consult the color spectrum to apply different tints to bulbs. Most standard lamps emit a clear light, which often appears yellow and does not illuminate an entire room evenly. To correct this problem, the interior of some bulbs is coated with a blue and green diffusion layer that brightens the light and allows it to illuminate more space. To reduce eye strain, bulbs designed for reading, or similar activities, are often larger than average and feature a white interior coating that produces a softer light.