A soap bubble (n = 1.35)is floating in air.If the thickness of the bubble wall is 300 nm,which of the following wavelengths of visible light is strongly reflected?
A)620 nm (red)
B)580 nm (yellow)
C)540 nm (green)
D)500 nm (blue)

Question

Quizplus · Accepted Answer

The condition for constructive interference in thin films is 2nt = mλ, where n is the refractive index, t is the thickness, and λ is the wavelength. For strong reflection, m should be an integer. For n = 1.35 and t = 300 nm, solving for λ gives approximately 540 nm, which corresponds to green light.

A Soap Bubble (N = 1