Can someone help me please? For most of the examples of thin film interference w

Question

Can someone help me please?

For most of the examples of thin film interference we've seen, the films are really thin! That's because we're working with visible or UV light, which have wavelengths shorter than 10-6 m. However, the principle is valid at any wavelength. So, consider a kiddie pool down at the neighborhood rec center. It has water 2 ft. deep and has a cement slab on the bottom. Which wavelength of EM radiation would encounter constructive interference by reflection from this pool, and which would suffer destructive interference? In what part of the spectrum are these wavelengths? Would it be possible to experimentally test for this effect? Explain.

Explanation / Answer

a)

For constructive interference path difference = n*wavelength

;n=0,1,2,3.......

depth = d = 2 ft .let theta = 0, order = m =1

Here path difference = 2d cos theta = 2*2*0.3048 = wavelength

wavelength = 1.2192 m , It is in very High frequency -High frequency spectrum.

for destructive interference, path difference = (n+0.5)*(wavelength)

;n=0,1,2,3.......

depth = d = 2 ft .let theta = 0, order = m =1

Here path difference = 2d cos theta = 2*2*0.3048 = 1.5*wavelength

wavelength = 0.8128 m

It is in Ultra High frequency- Ver High frequency spectrum.

b)It won't be possible, because we won't be able to see the interference as they are of high wavelength than visible light.

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