Thursday, December 15, 2011

What type of heat transfer is found in an electric bulb?

in anelectric bulb, the working principle is thermionic emission, where electrical energy is converted to heat energy. the tungsten filament in the bulb gets heated by passage of current to incandescence, at which it emits light. however, only 10% of electric energy is converted to light energy and 90% is wasted as heat energy, that's why these bulbs are very hot during operation and are not economical. nowadays, mostly flourescent lamps are being used producing almost no heat.|||Energy transfer in a light bulb:





Friction (resistance) caused by electrical current, friction (resistance) causes light and heat energy.





The heat is radiated into the environment.|||Hot eletron's to filiment, hot filiment to air, hot infrared radiation to surfaces, then is spreads from there in the same ways, atom to atom and energy wave to atom...

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