What are the different types of electric lights?
Today, there are many different types of electric lights. In incan-descent light, a bulb glows when electric current heats up a filament placed inside a glass bulb, to produce a yellowish-white light.
In fluorescent lights, an electric current is passed through mercury vapour inside a glasstube.The vapour gives off UV light that is absorbed by phosphor powder coated on the inside of the tube, to produce a visible blue-white light.
Another type of lighting is strip lighting. In this case, an electric current flows through a gas that is under low pressure. The gas gives off ultraviolet light, and this strikes a phosphor coating, making it fluorescent, so that it produces light. The colour of the light depends on the type of gas that is used. Alternatively, metal vapours can be used instead of a gas. For example, mercury vapour produces a blue light, while sodium vapour glows yellow. Sodium vapour lights are sometimes used in street lighting.
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