Question

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

Answer 1

Answer: (B)

From Hugen's 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.