Problem: A soap bubble is essentially a thin film of water surrounded by air. The colors you see in soap bubbles are produced by interference. (a) What visible wavelengths of light are strongly reflected from a 390 nm -thick soap bubble? (b) What color would a 390 nm thick soap bubble appear to be (green, purple, or yellow)?

FREE Expert Solution

Constructive interference in thin films (when the film material has a higher index of refraction):

2ηd=(m+12)λ

(a)

Refractive index of water, η = 1.33

d = 390 nm (10-9m/1nm) = 390 × 10-9 m

Solving for the wavelength, λ:

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Problem Details

A soap bubble is essentially a thin film of water surrounded by air. The colors you see in soap bubbles are produced by interference. 

(a) What visible wavelengths of light are strongly reflected from a 390 nm -thick soap bubble? 

(b) What color would a 390 nm thick soap bubble appear to be (green, purple, or yellow)?