question_answer

Mirrors '1, '2' and '3' are placed at right angles as shown below and a beam of light is made incident on mirror T. What will be the angle of reflection from mirror 3?

A) \[30{}^\circ \]

B) \[45{}^\circ \]

C) \[60{}^\circ \]

D)  The reflected ray from mirror ?2? will be parallel to the surface of mirror '3'

Correct Answer: C

Solution :

                      \[\angle ABP=\angle QBC={{30}^{o}}\] \[\angle BCF=\angle FCD={{30}^{o}}\] \[\therefore \]  \[\angle CDR={{30}^{o}}\] \[\therefore \]  Angle of incidence on mirror 3, \[\angle CDG={{60}^{o}}\] As per the laws of reflection \[\angle i=\angle r\] \[\therefore \]  Angle of reflection \[\angle GDS'={{60}^{o}}\]