Sunlight hit my cd and a rainbow was produced

AI Thread Summary
Sunlight hitting a CD produces a rainbow due to diffraction, not refraction. The CD's spiral of tiny pits encodes digital information and creates closely-spaced lines on its metallic layer. These lines function as a diffraction grating, dispersing light into its component colors. This phenomenon can be further explored by searching for "CD diffraction." Understanding this optical effect highlights the interplay between light and the physical structure of the CD.
Selnex
sunlight hit my cd and a rainbow was produced. can anyone tell me why ?
 
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refraction happen when the cd reflect the light
 
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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