Question

why a person sitting in front of the two palne mirrors.that intersect at right angle will see three images of himself​

Answer 1

Answer:

When two mirrors are kept at an angle and an object placed in between the mirrors, multiple images are formed due to reflection from one mirror on to the other. The number of images of the object formed depends on the angle between the two mirrors.

Explanation:

Answer 2

A person who is sitting in front of two plane mirrors which are at 90° to each other will see three images of himself due to the phenomenon of multiple images.

What are multiple images?

If there are two plane mirrors, inclined at a certain angle to each other, then we can see multiple images of the object due to multiple reflection.

How are multiple images formed?

Let's take the example of your question. If the two mirrors are kept at an angle of 90° to each other, then we can see 3 images of the object. Why? This is because the light coming from the object is incident on the first mirror. Due to reflection, this incident ray becomes reflected ray. Now this reflected ray from the first mirror acts as the incident ray for the second mirror and then reflection takes place from the second mirror. That's how we are able to see 3 images instead of 1.

Formula to calculate the number of images formed when two mirrors are kept at certain angle to each other:

$\frac {360°}{theta}$ -1 [Here theta is the angle between the two mirrors]

If two mirrors are kept parallel to each other, then infinite images will be formed.