You apply a material with n = 1.25 to a lens (n_g = 1.5)to make a nonreflective coating due to destructive interference at a wavelength (in a vacuum)of 555 nm.What is the minimum thickness of the coating that you need? A)56 nm B)110 nm C)220 nm D)280 nm E)140 nm

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Quizplus · Accepted Answer

The minimum thickness of the coating is one-quarter of the wavelength in the material, or:$$t = \frac{\lambda}{4n} = \frac{555 	ext{ nm}}{4(1.25)} = 110 	ext{ nm}$$

You Apply a Material with N = 1