help please, homework
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A generic bulb, with filament, works when the electrical current pass through that filament. As the resistance increases proportionally to the length and inverse to the thickness of the wire, the point is to make a very long and thin filament. For this reason, a malleable and strong material should be selected. It is also very important to use a material with high melting point, capable to support very high temperatures. Tungsten is known to have all those properties so, ultra thin and long filaments of tungsten are coiled thousands of times for this purpose.
When the current pass through them finds super resistance, such a big one that a lot of heat must be dissipated in order to balance the energy. That heat makes the filament to reach very high temperatures and so, it becomes incandescent, producing the emission of light.
The bulb contains a mixture of inert gases to prevent the destruction of that filament, otherwise, in presence of oxygen, it would chemically react and melt down (fusion).
When using some gases, such halogens or noble gases, they allow the pass of electrons between two distanced poles ( they are partially conductors of electricity) and their atoms become excited for a while. When those atoms go back to their normal conditions, they emit light in a particular wavelength, which is perceived by characteristic colours.
When the current pass through them finds super resistance, such a big one that a lot of heat must be dissipated in order to balance the energy. That heat makes the filament to reach very high temperatures and so, it becomes incandescent, producing the emission of light.
The bulb contains a mixture of inert gases to prevent the destruction of that filament, otherwise, in presence of oxygen, it would chemically react and melt down (fusion).
When using some gases, such halogens or noble gases, they allow the pass of electrons between two distanced poles ( they are partially conductors of electricity) and their atoms become excited for a while. When those atoms go back to their normal conditions, they emit light in a particular wavelength, which is perceived by characteristic colours.
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http://www.youtube.com/watch?v=RSf9aEETn…
It explains it fully.
It explains it fully.