- #1
Terraist
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Hi, I'm a high school physics student and I'm having a lot of trouble with thin film interference
A thin layer of oil (noil=1.25) is floating on water (n=1.33). How thick is the oil in the region that strongly reflects green light (λ=556nm)?
noil/nwater = λwater/λoil
t = mλ/2, where t is thickness of the film, m is order of interference maxima (i'm not sure about this one)
1.25/1.33 = 556/λ
λ=592 nm
t=mλ/2
=(1)(592)/2
=296 nm
(ans in book 222 nm)
I'm not entirely sure of what I'm doing here. I'm trying to just find the right formula to plug the variables in and I don't grasp the principles behind it. If someone could shed some light on the subject and provide some tips on how to solve similar problems it would be greatly appreciated.
Homework Statement
A thin layer of oil (noil=1.25) is floating on water (n=1.33). How thick is the oil in the region that strongly reflects green light (λ=556nm)?
Homework Equations
noil/nwater = λwater/λoil
t = mλ/2, where t is thickness of the film, m is order of interference maxima (i'm not sure about this one)
The Attempt at a Solution
1.25/1.33 = 556/λ
λ=592 nm
t=mλ/2
=(1)(592)/2
=296 nm
(ans in book 222 nm)
I'm not entirely sure of what I'm doing here. I'm trying to just find the right formula to plug the variables in and I don't grasp the principles behind it. If someone could shed some light on the subject and provide some tips on how to solve similar problems it would be greatly appreciated.