A ray of light has a glancing angle of 60° on a plane mirror. What is the angle of deviation of the ray?
A
140°
B
60°
C
30°
D
120°
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
Glancing angle = 60°
Angle of incidence i = 90\(^\circ\) - 60\(^\circ\) = 30\(^\circ\)
Angle of deviation δ = 180\(^\circ\) - 2i = 120\(^\circ\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #78304)