Question

Draw a neat two ray diagram for the formation of images in two plane mirrors, when mirrors are at facing each other.

Answer 1

When two mirrors are parallel to each other

Consider two plane mirrors XY and PQ facing each other and ‘A’ as an object situated anywhere between them (See figure).
It is clear that mirror XY forms its image in mirror PQ and vice versa. These images by themsleves will act as image mirror or virtual mirrors.
Let us consider the normal incidence towards the mirror XY for object A. First of all an image X₁ is formed as far behind, as the object is in front of it. This image X₁ will fall in front of mirror PQ, and hence, forms an image X₂. The image X₂ falls in front of mirror XY and hence, forms an image X₃. Thus, it continues and infinite images can be formed.
Similarly, taking normal incidence for mirror PQ image P₁,P₂, P₃ etc. are formed.
In order to draw ray diagram, from point A, draw a divergent beam, meeting mirror PQ at points 1 and 2. With P₁ as a reference point, draw rays 1, 3, and 2, 4 meeting mirror XY. With P₃ as reference point draw rays, such that they enter the eye.