Law of Reflection in Plane Mirrors

Steps:

• Draw the normal perpendicular to the mirror at the point of incidence.
• Measure the angle of incidence as the angle between the incident ray and the normal.
• The diagram labels the relevant angle as 50° relative to the normal.
• By the law of reflection, the angle of reflection equals the angle of incidence, so both are 50°.

Why D is correct:

• The law of reflection states that for a plane mirror, the angle of incidence always equals the angle of reflection, and the diagram shows both as 50°.

Why the others are wrong:

• A: Uses 40° instead of the diagram's 50° marking.
• B: Angles unequal (40° ≠ 50°), violating the law of reflection.
• C: Angles unequal (50° ≠ 40°), violating the law of reflection.

Final answer: D