Question

If two plane mirrors be kept at an angle of ${120}^0$ to each other, the number of images of a object, kept between the two mirror is

• A. $2$
• B. $3$
• C. $4$
• D. $5$

Answer 1

Answer: (A)

$2$

The number of images formed between two mirrors kept at some angles is given as

$n=\left(\frac{{360}^{\circ }}{\theta }\right)-1$

Where $n$ is the number of images and $\theta$ is the angle between the mirrors.

Given that the angle between the mirrors is $\theta ={120}^{\circ }$, hence

$n=\left(\frac{{360}^{\circ }}{{120}^{\circ }}\right)-1$

$n=3-1$

$n=2$ .