Question

Two plane mirrors are placed at an angle of ${120}^{\circ }$ and a man combing his hair is standing at an asymmetric position. How many images will he see?

• A. $2$
• B. $3$
• C. $4$
• D. $5$

Answer 1

The correct option is B $3$

Given:
Angle between the mirrors, $\theta ={120}^{\circ }$
So, $n=\frac{{360}^{\circ }}{\theta }=\frac{{360}^{\circ }}{{120}^{\circ }}=3$
As $n$ is odd and man is at asymmetrical position with respect to mirrors, hence, the number of images,
$n=3$

Alternative:


Assuming object makes an angle $x$ with one of the mirror. From the above figure, it is evident that no matter what the value of $x$ is assumed, the angle of the fourth image will be greater than ${180}^o$. Hence total number of images formed will be 3.