Question

A ray of light strikes a mirror at an angle of ${60}^o$ to the normal. The mirror is then rotated ${18}^o$ anticlockwise, What is the angle that the initial reflected ray and final reflected ray will have?

• A. ${18}^o$
• B. ${20}^o$
• C. ${36}^o$
• D. ${54}^o$

Answer 1

The correct option is C ${36}^o$

When the mirror rotates , the angle of reflection rotates too. so,the angle of reflection rotates by $2\times 18={36}^0$

since,the angle of reflection $=$ angle of incidence.

so,the deflection will be same.