True or false: ordinary lightbulbs provide fluorescent light.  

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This is false. Ordinary screw-in lightbulbs produce light through a phenomenon called incandescence. They're called incandescent lights. They contain a very thin filament of tungsten wire that's part of the circuit. Tungsten has a high resistance. When electrons flowing through the circuit enter the thin wire the resistance causes heat...

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This is false. Ordinary screw-in lightbulbs produce light through a phenomenon called incandescence. They're called incandescent lights. They contain a very thin filament of tungsten wire that's part of the circuit. Tungsten has a high resistance. When electrons flowing through the circuit enter the thin wire the resistance causes heat to build up and the wire becomes hot and glows. Tungsten is used because of its high melting point. The sealed glass bulb contains argon gas which is inert and won't oxidize the tungsten.

Fluorescent lightbulbs produce light through a different process. A fluorescent light contains a small amount of vaporized mercury, usually along with an inert gas. They are sealed in a glass tube under low pressure. There are electrodes at each end of the sealed tube. High voltage across the electrodes moves electrons through the gas in the tube, and in doing so energizes electrons in the mercury atoms. The absorbed energy is emitted as photons of light that are in the ultraviolet region and largely invisible to people. When the uv light strikes the white phosphor coating on the inside of the tube its electrons absorb energy and emit light in the visible region. This phenomenon is called fluorescence, giving this type of light its name.

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