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I understand that a florescent light bulb radiates light as a result of exciting mercury in the bulb with electrons and those electrons are emitted by a filament.

What is the highest temperature that the filament ever gets? At what point does it reach that temperature: startup or some time later? Does the filament glow at any point or does it emit electrons without glowing?

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up vote 4 down vote accepted

Watch a fluorescent light while the starter is operating : the glow at either end is from the filaments acting as heaters. From the warm white colour, probably about 2500K. When the starter opens and the main lamp strikes, the filaments no longer glow.

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