Question

If a wave hits a smooth surface at an angle of incidence of 40 degrees, the angle of reflection is

A. 40 degrees.
B. 0 degrees.
C. 80 degrees.
D. 90 degrees.

Answer 1

If a wave hits a smooth surface at an angle of incidence of 40 degrees, the angle of reflection is 40 degrees.

Answer 2

As the surface given is a smooth surface, we can use specular reflection. According to the law of specular reflection, the angle of incidence equals the angle of reflection, so it will also be 40°. Answer is A.