Question

Question 13
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?

Answer 1

As per the laws of reflection
The angle of incidence $\angle i=angleofreflection\angle r$
Here as given $\angle i+\angle r={90}^{\circ }$
$\therefore \angle i+\angle i={90}^{\circ }$
or $\angle i=\frac{90}{2}={45}^{\circ }$
Hence angle of incidence of a ray = 45 degree