Today, these are many different types of electrical lights. In incandescent 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 vapor inside a glass tube. the vapor 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 a phosphor coating making it fluorescent, so that it produces light. The color of the type of gas that is used. Alternatively, metal vapors can be used instead of a gas. For example, mercury vapor glows yellow. Sodium vapor lights are sometimes used in street lighting.