Question

Two plane mirrors are inclined at angle $\theta$. An optical ray $AB$ is incident on a mirror at an angle $2\theta$ with the mirror, as shown. The reflected ray from the second mirror, $CD$ is perpendicular to the incident ray. Find angle $q$-

Answer 1

$(90-i)+\theta +(90-r)=180$
$⟹\theta =i+r={45}^o$
$90+2i+2r=180$
$i+r=\frac{90}{2}=45$