Light wave Interference - Angler Fish Problem

[aatari]

Hi Guys, I have attempted to solve the following question and was hoping someone can have a look and give some feedback. Any help will be greatly appreciated.

Thanks!

1. Homework Statement
Angler fish emit light through bioluminescence. An angler fish is swimming in a fish tank that has a film on the inside of the glass. The water in the tank has an index of refraction of 1.10, the film has an index of refraction of 1.21 and the glass has an index of refraction of 1.40. The film is 90.0 nm thick, and is such that the light reflecting back at the angler fish has been minimized. Find the wavelength of the angler fish’s light.

Homework Equations

PD = (n − ½)λ
λ = 2t(2n)

The Attempt at a Solution

 

[Charles Link]

Water normally has an index of refraction of $n= 1.33$. An index of $n=1.10$ is not correct. You can solve for the wavelength that such a film will result in being an anti-reflection coating for the information as given, but it is very hypothetical.

 

[aatari]

Water normally has an index of refraction of $n= 1.33$. An index of $n=1.10$ is not correct. You can solve for the wavelength that such a film will result in being an anti-reflection coating for the information as given, but it is very hypothetical.

That is true that water has the index of refraction n = 1.33. However, since the question uses the value of n = 1.10, I am using that to solve the problem.

So other than that is my solution correct?

 

[Charles Link]

That is true that water has the index of refraction n = 1.33. However, since the question uses the value of n = 1.10, I am using that to solve the problem.

So other than that is my solution correct?

For the information given, your solution looks correct.