[Construction – Section 99]
LIGHT BULBS
The light bulb is an artificial source, in which an electrical conductor heated by electricity and thereby to emit light, and thus the light is generated.
In a light bulb, an electrical conductor, which is the wire that flow so much heat that it glows. This is the thermal radiation. The recorded electrical power is a part, in the form of electromagnetic radiation that is in the infrared and visible light emitted. The rest is on heat conduction and convection of heat and glass flask filled, and also to the lead wires and the wires holding filament made.
The filament emits radiation planck according to the law, so that the radiation with increasing temperature in accordance with the Viennas postponement of the law to smaller wavelength shifts. To make the most visible light to maintain and even to make the most naturally white light appears, then it is seeking, the maximum radiation by temperature increase from the long-infrared radiation in the range of visible light to move.
The maximum temperature is due to the properties of the material of the filament. In order to enable high temperatures, used today for the filaments refractory metal tungsten. It has a melting temperature of about 3420 ° C.