Question

In the figure shown, the image of the real object is formed at point I. AB is the principal axis of the mirror. The mirror must be .

A. Concave and placed towards right of I
B. Concave and placed towards left of I
C. Convex and placed towards right of I
D. Convex and placed towards left of I

Answer 1

Note first if the image formed is real and inverted or virtual and erect. Then, tell which type of mirror can produce the type of image. You can then assume the mirror is placed on one of the sides of the image I and then check if the assumption is correct or not.

Complete step by step answer:
It can be noted clearly in the diagram that the image formed is real and inverted. In spherical mirrors, convex mirrors never produce real and inverted images of the object. Therefore, options C and D are definitely incorrect. Now we are left with options A and B.
Let us assume that the mirror is placed towards the left of the image (). Then, the image is towards the right of the mirror and the object is towards its left. Since a mirror reflects the light incident on it, the image formed towards the right of the concave mirror can not be real. In other words, the image formed by a concave mirror is real only if the image and object lie on the same side, which is left according to convention of the mirror. That is, option B is also incorrect.
The option we are left with is option A and it is correct.

So, the correct answer is “Option A”.

Note: Image formed by convex mirror is always virtual and erect. For a mirror, the image formed towards the left will be real and the image formed towards right will be virtual.
Real images can be formed on a screen while virtual images appear to be inside the mirror.