Question

II1. A plane wave is incident on a glass-air interface with a sinusoidal boundary from the high index side. The period of the surface is d; the wavelength of the light is 2; the angle of incidence is 6. Discuss fully how the incident wave is scattered by the interface.

Answer 1

First of all we can discuss about reflection of light waves (plane electromagnetic waves) . Reflection of light occurs when light rays strike the interface between the two media's here it is glass -air interface a part of the incident light is turned back to the same media . Reflection is of two types

• Regular reflection : if the reflection takes place on a perfect plane of surface. Then one part of reflected light has more intensity and directed in one direction. And the other part only have small intensity and directed to other direction .
• Diffused reflection : This type of reflection occurs when the surface is rough. Then the light reflected from different points of surface and all are directed to different directions due to the irregularity of surface.Then due to this we can see an object from any position.

Here in the question they mentioned that the boundary is like a sinusoidal type so it is a type of irregular surface. So here the reflection is diffused type reflection. Ie, the wave get reflected by different points and reflected to different directions. Example for a diffused reflection is reflection from a news paper, wall etc...

Hope you ok with this and thank you.