Question

A ray reflected successively form to p[lane mirrors inclined at a certain angle undergoes a deviation of ${300}^0.$ Then the no. of images observable is $?$

• A. $11$
• B. $15$
• C. $12$
• D. $20$

Answer 1

The correct option is A $11$

Angle of deviation is given by$:$

$\delta -={360}^0-2\theta$

$\Rightarrow {300}^0={360}^0-2\theta$

$\Rightarrow \theta ={30}^0$

Then number of images produced

$n=\frac{{360}^0}{\theta }-1$

$\Rightarrow n=\frac{{360}^0}{{30}^0}-1=11$

Hence,

option $\left(A\right)$ is correct answer.