Question

If the angle of incidence is 30${}^{\circ }$ then find the unknown angle.

• A. 30⁰
• B. 60°
• C. 90°
• D. 0⁰

Answer 1

The correct option is B

60°

Law of reflection states,

$\angle$ i = $\angle$ r = 30${}^{\circ }$

Also, we know the normal makes an angle of 90${}^{\circ }$ at the surface. Let the unknown angle be x.

$\Rightarrow$ x + 30${}^{\circ }$ = 90${}^{\circ }$

$\Rightarrow$ x = 60${}^{\circ }$