Two flat mirrors (M ₁ and M ₂) are perpendicular to each other. A monochromatic, laser beam hits the surface of M ₁, at an angle θ, 15.0 cm from the intersection of the two surfaces. After reflection from M ₁, the beam of light hits the surface of M ₂ 25.0 cm away from the intersection. Determine the angle of incidence θ .

• A. 31.0°
• B. 39.0°
• C. 51.0°
• D. 59.0°

Answer: (A)