A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:
A) 30°

B) 45°

C) 60°

D) 90°

Question

A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:
A) 30°

B) 45°

C) 60°

D) 90°

Philoid · Accepted Answer

Ray PQ strikes the mirror AB at Q and gets reflected along QR according to the laws of reflection. The ray QR incident on mirror BC makes an angle of 30° with the mirror. So, the angle of incidence on this mirror is 90° - 30° = 60°. Hence, the angle of reflection is also 60°.

A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:A) 30°B) 45°C) 60°D) 90°

A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second mirror is:
A) 30°

B) 45°

C) 60°

D) 90°