Question

If an incident light ray is reflected back along its original path by a plane mirror, then its angle of incidence is:

• A. $0^o$
• B. ${90}^o$
• C. ${45}^o$
• D. ${30}^o$

Answer 1

The correct option is A $0^o$

If an incident light ray is reflected back along its original path by a plane mirror, then its angle of incidence is 0 degrees.

The angle of incidence is the angle that an incident line or ray makes with the line perpendicular to the surface; at the point of incidence. For a ray to trace back its path, the ray has to fall normally onto the surface of reflection.