Problem 5.174

A light wave falls normally on the surface of glass coated with a layer of transparent substance. Neglecting secondary reflections, demonstrate that the amplitudes of light waves reflected from the two surfaces of such a layer will be equal under the condi. tion \(n^{\prime}=\sqrt{n},\) where \(n^{\prime}\) and \(n\) are the refractive indices of the layer and the glass respectively,