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Does Color Filter Change The Frequency Of Light?

quantum mechanics electromagnetic spectrum

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#1 vibhorsethi

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Posted 05 September 2018 - 01:02 AM

If I glow a white LED bulb and then put a color filter around it (for example, a red color filter or a violet color filter) , then will it change the frequency of light.



#2 exchemist

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Posted 05 September 2018 - 02:50 AM

If I glow a white LED bulb and then put a color filter around it (for example, a red color filter or a violet color filter) , then will it change the frequency of light.

No.

 

The clue is in the word "filter". If you filter coffee, does the filter change the coffee? No, it just selectively removes the grounds.

 

A light filter absorbs many frequencies and thus transmits a narrower range of them than is present in the incident light. If you have white light and a red filter, the filter absorbs all the frequencies higher than those that give red light, i.e. absorbs frequencies > 484THz approximately.

 

See here for frequency and wavelength ranges of visible light:  https://en.wikipedia...isible_spectrum