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

7: a: A thin film of oil (n_{2}=1.2 and t(thickness) = 600nm) lies on top of some water (n_{3}=1.33) after spilling from an oil tanker. What wavelengths of visible light would be bright in reflection? use n_{1}= 1 (air)

2. Relevant equations

CI (constructive interference): 2t = (m+1/2)Lambda

DI (destructive interference): 2t = mLamda

Lamda = Lamda/n

Layers of film

air= n_{1}

oil = n_{2}

water = n_{3}

3. The attempt at a solution

The problem asks for the bright areas so I used the constructive interference equation. my set it up as one part of the wave being completely reflected while another part of the wave refracted into the oil and then is reflected by the water and refracted into the air. I can't figure out what to do next.

The answer is: (720nm, 480nm)

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# Homework Help: Interference and Defraction

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