Question

The nonreflective coating on a camera lens with an index of refraction of 1.21 is designed to minimize the reflection of 570-nm light. If the lens glass has an index of refraction of 1.52, what is the minimum thickness of the coating that will accomplish this ta

Answer 1

Answer: 117.8 nm

Explanation:

Given,

Nonreflective coating refractive index : n = 1.21

Index of refraction: $n_0$ = 1.52

Wave length of light = λ = 570 nm = $570\times10^{-9}\ m$

$\text{ Thickness}=\dfrac{\lambda}{4n}$

$=\dfrac{570\times10^{-9}\ m}{4\times1.21}\\\\\approx\dfrac{117.8\times 10^{-9}\ m}{1}\\\\=117.8\text{ nm}$

Hence, the minimum thickness of the coating that will accomplish= 117.8 nm