What wavelength monochromatic source in the visible region (390 to 710 nm)can be used to constructively reflect off a soap film (n = 1.46)in air if the film is 288 nm thick?
A) 561 nm
B) 480 nm
C) 587 nm
D) 467 nm

Question

Quizplus · Accepted Answer

For constructive interference in a thin film, the condition is 2 * n * d = m * λ, where n is the refractive index, d is the thickness, and λ is the wavelength. For m = 1, 2 * 1.46 * 288 nm = 561 nm, which is within the visible range.

What Wavelength Monochromatic Source in the Visible Region (390 to 710