What is the thickness of a soap bubble film (n = 1.38) that results in a constructive interference in the reflected light if this film is illuminated by a beam of light of wavelength 610 nm?

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Quizplus · Accepted Answer

For constructive interference in a thin film, the condition is 2 * n * t = m * λ, where n is the refractive index, t is the thickness, λ is the wavelength, and m is an integer (for the first order, m=1). Solving for t gives t = λ / (2 * n) = 610 nm / (2 * 1.38) = 221.74 nm, which rounds to 222 nm. However, for the first minimum thickness, we use m=0.5, giving t = 610 nm / (4 * 1.38) = 110.87 nm, which rounds to 111 nm.

What Is the Thickness of a Soap Bubble Film (N