In the diagram above, an incident ray AY makes an angle of 30o with the normal XY. If the mirror is rotated anticlockwise about Y through an angle of 20o, while AY is fixed, what angle will the reflected ray now make with the incident ray?
- 70o
- 80o
-
100o
- 120o
The correct answer is: C
Explanation
The reflected ray will rotate through angle 2 x 20º = 40º
The reflected ray will now make angle 30º + 30º + 40º = 100º with the incident ray(30º + 30º since i = r)