What is the minimum thickness of a soap bubble film with refractive index 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?
A)222 nm
B)111 nm
C)333 nm
D)444 nm
E)555 nm

Question

Quizplus · Accepted Answer

The formula for the minimum thickness for constructive interference in reflected light for a soap bubble film is:

t = (m+0.5)λ/(2n)

where t is the thickness of the film, m is an integer (0, 1, 2, ...), λ is the wavelength of the incident light, and n is the refractive index of the film.

In this case, we know λ = 610 nm and n = 1.38. We want to find the minimum thickness that results in constructive interference, so we need to use m = 0.

Plugging in these values, we get:

t = (0+0.5) * 610 nm / (2 * 1.38) = 111 nm

Therefore, the answer is B) 111 nm.

What Is the Minimum Thickness of a Soap Bubble Film