Question

Two plane mirrors are inclined at ${70}^o$. A ray incident on one mirror at angle $\theta$, after reflection falls on second mirror and is reflected from there parallel to first mirror. The value of $\theta$ :

• A. ${45}^o$
• B. ${30}^o$
• C. ${55}^o$
• D. ${50}^o$

Answer 1

The correct option is D ${50}^o$

In the triangle formed in figure-
$70°+70°+90°-\theta =180°$

$\theta =50°$