Answer:
0.41 μm or 410 nm
Explanation:
Given that
Soap thickness, t = 77.1 nm = 77.1*10^-9 m
Refractive index of water, μ = 1.33
The longest wavelength for constructive wavelength is given by the formula
2μt = (n - 1/2)λ
Making λ the subject of the formula gives
λ = 2μt / (n - 1/2), substituting the values, we have
λ = (2 * 1.33 * 77.1*10^-9) / 1/2
λ = (2.66 * 77.1*10^-9) / 1/2
λ = 2.05*10^-7 / 1/2
λ = 4.10*10*^-7 m
λ = 0.41 μm
The longest wavelength requested therefore is 0.41 μm or 410 nm
