Let ’s start with a normal electriclight bulblike you see in any normal household lamp . A normal light electric-light bulb is made up of a pretty enceinte , thin , frosted glass gasbag . Inside the glass is a gas such as argon and/or nitrogen . At the center of the lamp is atungstenfilament . Electricity heats this fibril up to about 4,500 degrees F ( 2,500 degree Celsius ) . Just like any hot metal , the atomic number 74 gets " white red-hot " at that warmth and emits a nifty bargain of seeable light in a summons calledincandescence . SeeHow Gas Lanterns Workfor more information on incandescence .
A normal light bulb is not very effective , and it only lasts about 750 to 1,000 hour in normal use . It ’s not very efficient because , in the process of radiate visible light , it also radiates a huge amount of infrared heat – far more heat energy than light . Since the role of a light bulb is to engender light , the heat is wasted vim . It does n’t last very long because the tungsten in the filament evaporates and deposit on the drinking glass . finally , a thin smirch in the filament causes the filum to break , and the electric light " combust out . "
Ahalogen lampalso use a tungsten filament , but it is encased inside a much smallerquartz envelope . Because the gasbag is so close to the filament , it would melt if it were made from methamphetamine . The gas inside the envelope is also different – it consist of a gas from thehalogen mathematical group . These gases have a very interesting attribute : They combine with tungsten vapor . If the temperature is in high spirits enough , the halogen gas will combine with tungstenatomsas they disappear and redeposit them on the filament . Thisrecyclingprocess lets the fibril last a lot longer . In add-on , it is now potential to execute the filament hotter , meaning you get more light per whole of Department of Energy . You still get a mint of estrus , though ; and because the crystal envelope is so unaired to the fibril , it isextremelyhot compare to a normal visible radiation bulb.
