Why does the filament glow in the lamp shade and burn in the air?
A: in fact can also be a straight wire, we often use is mainly urban spiral, you don't see. Incandescent lamp (electric) incandescent lamp (electric), using the method of electricity will be heated to incandescence object state and light lamp. Note: the light body is usually made of tungsten and its structure can be straight wire. Single screw, double helix, or triple helix. Why did the tungsten filament curl into a spiral?
Answer: because this can lengthen the life of the bulb. Tungsten wire melting point (3410 ℃), in a vacuum can be heated to 2200 ℃, spiral wire coil, increases the resistance of tungsten wire, allowing more of the electric energy can be converted into heat energy. Increase the length of the filament in the chimney and bulb structure is compact, and let the light source is more concentrated. As a result of heat distribution in long wire circle, then change will reduce the temperature of filament, naturally reduce tungsten sublimation, so then prolong the life of the bulb.
The lamp shade is filled with inert gas or nitrogen, and does not react with tungsten. But in the air, the temperature of the tungsten filament immediately reacts with the oxygen, producing the oxide, and the tungsten filament is broken.
