(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

White light was shone vertically down on a cd tilted 5°, with adjacent tracks d = 720 nm. An observer some distance away observes a color of light. Determine that wavelength of light observed. (Refer to picture attachment)

2. Relevant equations

finding path difference

3. The attempt at a solution

I understand that finding the path difference is key to solving this problem. So, i found the path difference to be simply:

d cos (90+ 5 - ∅) = (1)(λ)

But the answer wrote path difference =

d cos (90 + 5 - ∅) - d cos (90 - 5)

Using the provided answer, it didnt make sense to me for the additional term of ' d cos (90 - 5)' to be there?

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# A question on CD diffraction

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