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Seeing the spectrum out of order on a CD

  1. Sep 14, 2011 #1
    So I built a little homemade CD/cardboard box spectrometer just for fun, but a weird thing happens with it. I keep seeing the spectrum of light out of order with it:

    Here's what I see from my computer monitor:
    [PLAIN]http://img200.imageshack.us/img200/926/monitorbs.jpg [Broken]

    Here's what I see from a tungsten flashlight:
    [PLAIN]http://img84.imageshack.us/img84/4448/tungsten.jpg [Broken]

    Now, I know that I didn't make the slit anywhere near small enough (it's about 1.5mm), but whenever I hold a CD and tilt it in my hand up to these sources the spectrum on it in the right order.

    I'm not sure why it's doing this, and I don't know enough about light to really answer it.
    Last edited by a moderator: May 5, 2017
  2. jcsd
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