question_answer

A ray of light is incident on a plane mirror at an angle of\[60{}^\circ \]. The angle of deviation produced by the mirror is

A)  \[120{}^\circ ~\]

B)  \[30{}^\circ \]

C)  \[60{}^\circ ~\]

D)  \[90{}^\circ \]

Correct Answer: C

Solution :

Here, angle of incidence, \[i={{60}^{o}}\] \[\therefore \]Angle of deviation \[\delta ={{180}^{o}}-(i+r)\] \[={{180}^{o}}-2i\] \[(As\,i=r)\] \[={{180}^{o}}-2\times {{60}^{o}}={{60}^{o}}\]