Answer:
λ= 2455 nm
Explanation:
Constructive interference occurs when the optical path difference is equal to an integer multiple of wavelength. Let's examine the reflection on each face
On the first surface we go from a lower medium refractive index (air) to one with a higher index (film), whereby a phase change of pi (180º) is introduced. On the second surface instead of the beginning of refraction, it is from a higher index to a smaller one, so there is no phase change, with this we can write the normal interference equation.
2 t = (m + ½)
The term lann is the wavelength in the film that is related to the wavelength in the air by
= λ / n
2t = (m + ½) λ / n
λ = 2t n / (m + ½)
For the first constructive interference m = 0
λ = 2 0.448 10⁻⁶ 1.37 / (0 + ½)
λ = 2,455 10⁻⁶ m
λ = 2,455 10⁻⁶ m (10⁹ nm / 1m)
λ= 2455 nm
For m = 1
λ = 2 0.448 10-6 1.37/ (1 + ½)
λ = 0.81835 10-6 m
λ = 818 nm
We can observe that the length and where it corresponds to ultraviolet light, so there is no constructive interference for visible light.