Problem 5.81

To decrease light losses due to reflection from the glass surface the latter is coated with a thin layer of substance whose refractive index \(n^{\prime}=\sqrt{n}\), where \(n\) is the refractive index of the glass. In this case the amplitudes of electromagnetic oscillations reflected from both coated surfaces are equal. At what thickness of that coating is the glass reflectivity in the direction of the normal equal to zero for light with wavelength \(\lambda\) ?