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Sunlight hit my cd and a rainbow was produced

  1. Jun 11, 2003 #1
    sunlight hit my cd and a rainbow was produced. can anyone tell me why ?
    Last edited by a moderator: Feb 5, 2013
  2. jcsd
  3. Jun 11, 2003 #2
    refraction happen when the cd reflect the light
  4. Jun 11, 2003 #3


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    Staff Emeritus
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    It is not refraction which causes the rainbow, it is diffraction. The CD is a spiral of tiny pits which encode the digital information. The spiral forms a set of roughly concentric closely-spaced lines on the disc's metallic inner layer. These lines act as a diffraction grating, and spread the light out into its constituent colors.

    You can google "CD diffraction" and find all the info you'd ever want. :)

    - Warren
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