Questions on light reflection and refraction for msc physics
Answers
The Laws of Reflection govern the reflection of light-rays off smooth conducting surfaces, such as polished metal or metal-coated glass mirrors.
Consider a light-ray incident on a plane mirror, as shown below.
The Laws of Reflection state: !. the incident ray, the reflected ray, and the normal to the surface of the mirror all lie in the same plane.
2. the angle of incidence i = the angle of reflection r. Both angles are measured with respect to the normal to the mirror.
The Laws of Reflection also hold for non-plane mirrors, provided that the normal at any point on the mirror is understood to be the outward pointing normal to the local tangent plane of the mirror at that point.
For rough surfaces, the Laws of Reflection remains valid. It predicts that rays incident at slightly different points on the surface are reflected in completely different directions, because the normal to a rough surface varies in direction very strongly from point to point on the surface. This type of reflection is called diffuse reflection, and is what enables us to see non-shiny objectsL