2006-09-11 02:19:21 · 5 answers · asked by santhosh 1 in Science & Mathematics ➔ Physics
The light bulb filament burns out because huge amounts of current are flowing through it to make it glow so brightly. If it were exposed to oxygen, the heat would facilitate rapid oxidation, and the delicate, thin filament would disintegrate. A heater coil is a sturdy piece of resistive metal, and it doesn't have as much current flowing through it. As a result, oxidation is not going on at an extreme rate, and the bulk of the material is sufficient to give the heating element as long as life as the rest of the components. If a heater coil were made to carry a current sufficient to make it glow white-hot, it probably would start to oxidize and disintigrate fairly quickly.
2006-09-11 02:26:10 · answer #1 · answered by DavidK93 7 · 1⤊ 1⤋
Because the filament of a light bulb burns much hotter and would oxidize very rapidly if exposed to air; heater coils are so much bigger and much cooler.
2006-09-11 02:38:51 · answer #2 · answered by bruinfan 7 · 0⤊ 1⤋
A light bulb filament is much hotter in order to produce white light.
Heater filaments are made of a different material that would melt at that temperature, but resists oxidation at the temperature at which it operates.
2006-09-11 02:27:10 · answer #3 · answered by novangelis 7 · 0⤊ 1⤋
David and Ashish gave good answers, but I just had to add site on light bulbs for those really, really interested in light bulbs.
http://bulbcollector.com/index.html
They even have a forum where you can discuss your favorite light bulbs.
http://bulbcollector.com/forum/index.php
This discussion about light bulb filaments is a true classic.
http://bulbcollector.com/forum/index.php?topic=563.0
Those of you more interested in vacuum tubes than light bulbs don't have to feel left out. If you scroll down the left side of the home page, they even have a section for you guys. Here's their radio tube gallery.
http://bulbcollector.com/gateway/Vacuum_Tubes/Radio_Tubes
Edit: How could someone give me a thumbs down rating with those incredible links I provided. Those lightbulbs are so cool! Uh, how come you're all looking at me so funny. Oh, geez, I'm really sick, aren't I?
2006-09-11 02:55:19 · answer #4 · answered by Bob G 6 · 0⤊ 1⤋
A bulb Filament is made of Tungsten(W), which has a property of glowing in Vaccum or presence of Inert Gases, however when air is their it simply oxidizes itself to Tungesten oxide.... which we called as burning. however,
Heater coil is made of iron or some other resitant material which does not oxidise at that tempertaure & does not melts... So the current flowing thru it make is hot due to resitance.. but due to is non oxidizing property it does not burn.....
2006-09-11 02:33:48 · answer #5 · answered by Ashish Samadhia 3 · 3⤊ 1⤋