A fluorescent lamp is a type of electric lamp that excites mercury vapor to create luminescence. Fluorescent lights are more efficient than conventional incandescent lampss because less of the energy is converted to heat. Instead, most is converted to usable light.
The fluorescent lamp was invented in 1900 by Edmund Germer.
A fluorescent light bulb is filled with a gas containing argon and mercury vapor, sometimes referred to as plasma. The inner surface of the bulb is coated with a fluorescent paint made of varying blends of metallic and rare-earth phosphor salts. The bulb's cathode bombards the vapor with electrons causing it to emit ultraviolet (UV) light. The UV light is absorbed by the bulb's fluorescent coating. The coating reradiates the energy at longer frequencies, to emit visible light. The blend of phosphors controls the color of the light. The bulb's glass prevents the harmful UV light from escaping.
Fluorescent light bulbs come in many shapes and sizes. An increasingly popular one is the “compact fluorescent” (CF) light which screws into a regular light bulb socket. Their advantages over regular incandescent bulbs are their long life (6,000 to 10,000 hours instead of 1,000 hours) and energy savings due to their lower wattage; a 17-watt CF bulb gives the same amount of light as a 75-watt incandescent bulb.
Unfortunately, many people find the color spectrum produced by fluorescent lighting to be harsh and displeasing. It is common for a healthy person to appear with a sickly bluish skin tone under fluorescent lighting, and many pigments have a slightly different color when viewed under fluorescent light versus incandescent. However, some manufacturers have attempted to make fluorescent light bulbs that produce more “natural” light.
Residential use of fluorescent lighting remains low, but schools and businesses find the cost savings of fluorescents to be significant and only rarely use incandescent lights.
Because they contain mercury, a toxic material, fluorescent bulbs must be properly disposed of in many areas throughout the world.