A laser beam strikes a plane mirror's reflecting surface with an angle of incidence of 43°.What is the angle between the incident ray and the reflected ray?
A)43°
B)86°
C)45°
D)90°
E)0°

Question

Quizplus · Accepted Answer

According to the Law of Reflection, the angle of incidence and the angle of reflection are equal. Since the angle of incidence is 43°, the angle of reflection is also 43°. Therefore, the angle between the incident ray and the reflected ray is 180°-43°-43°=94°. However, this angle is formed between the incident ray and the reflected ray if measured from a perpendicular line from the mirror surface. Therefore, the angle measured between the incident ray and the reflected ray is 180° - 94° = 86°. Therefore, choice B is the correct answer.

A Laser Beam Strikes a Plane Mirror's Reflecting Surface with an Angle