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Why does a light bulb light up a purple color when you put it in the microwave? Thanks

Sounds like you have been doing some hazardous experiments at home there... In fact, I have never heard of this before - and I cannot think of an explanation either. Sorry. Light bulbs have tungsten filaments and some gas (Argon I think) inside, and microwaves generate relatively high-frequency radiation. I assume the tungsten is absorbing most of the radiation and heating up, but not quite as hot as it normally gets when the light bulb is plugged in. But that is just a guess.

Arthur Smith

Normal light bulbs have only a partial vacuum in them; that is, they have a small gass pressure inside, or a small amount of gas (usually argon) in them. The microwave radiation is creating a plasma in the gas, which emits light.

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