Question

If angle between two plane mirrors is 120 degrees then how many images were formed

Answer 1

Answer:3

Explanation:

The number of images formed by a pair mirrors kept at an angle $\alpha$ is

$n=\frac{360}{\alpha } -1$  if $\frac{360}{\alpha }$ comes even.

$n=\frac{360}{\alpha }$      if $\frac{360}{\alpha }$ comes odd.

where $n$ is the number of images formed.

In our question,

$\alpha =120^{0}$

$\frac{360}{\alpha } =\frac{360}{120}=3$

It is odd,so $n=\frac{360}{120}=3$