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Q & A: prisms and colors

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Most recent answer: 04/19/2008
Q:
I was looking at the question about the prism. So if the prism separated the light into ROYGBIV, can I put the light back together using another prism? Will the light be white again when it comes out of the other prism? I have one more question. Are all of the lights going the same speed if I can put them back together with the second prism. I hope this makes sense. thank you
- trey
Austin,Tx
A:
Good questions. The answer is yes, the experiment of recombining the different colors to get back white light was done by Isaac Newton.
All the colors are going the same speed in a vacuum and nearly the same speed in air. They travel diffferent speeds in glass. So if instead of a steady beam you had a very short blip of white light, it souldn't recombine proeprly since the different colors would be delayed different amounts. You couldn't see that by eye, however, since the delays are too small.

Mike W.

(published on 04/19/2008)

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