Question

A light ray is incident on a flat surface, making an angle of ${30}^{\circ }$with the surface. What is the angle between the surface and the normal?

• A. ${30}^{\circ }$
• B. ${60}^{\circ }$
• C. ${90}^{\circ }$
• D. ${180}^{\circ }$

Answer 1

The correct option is C ${90}^{\circ }$

Normal is a line drawn perpendicular to the surface of mirror from the point where incident ray meets the surface of the mirror. So the angle between the surface and the normal is always ${90}^{\circ }$. It is independent of angle of incidence.