2007-12-13 07:37:07 · 2 answers · asked by pyromaniac2617 2 in Science & Mathematics ➔ Physics
When one turns a incandescent light bulb on its filament heats up quickly and cools off as as soon it is turned off. This mechanical expansion and contractions are inducing material fatigue in the filament.
2007-12-13 07:50:55 · answer #1 · answered by Edward 7 · 1⤊ 0⤋
Of course a bulb that is turned off (for considerable periods) will last longer than if constantly burned because the intense heat slowly vaporizes the filament. However, when a bulb's filament has weakened at a given point, and the light is turned on, the thin section will get even hotter than usual while current is highest before the entire filament temperature rises which increases electrical resistance. A bulb often pops when turned on just one more time because the weakened spot fails.
2007-12-13 16:00:42 · answer #2 · answered by Kes 7 · 0⤊ 0⤋