question_answer

When a ray of light is incident normally on a surface, then:

A)  total internal reflection takes place

B)  it passes undeviated

C)  it undergoes dispersion

D)  it gets absorbed by the surface

Correct Answer: B

Solution :

                 From Hugens principle, if the incident wave front be parallel to the interface of the two media\[(i=0),\]then the refracted wave front will also be parallel to the interface\[(r=0)\]. In other words, if light rays fall normally on the interface,   then   on passing to the second medium they will not deviate   from   their original path.