Question

Which of the 26 letters of English alphabet will form an image in a plane mirror which will be the same as the letter? Why do other images not form images identical to them?

Answer 1

Hint: In this question we are asked to name the letters of English alphabet who will form identical images of themselves in a plane mirror. To solve this, we will first study the causes that make the letter to form an identical image of itself when placed in front of the plane mirror. We will then see the letters following these reasons.

Complete answer:
To solve this question we will first discuss how an image is formed in a plane mirror. We know that, for a plane mirror the image formed will be the flipped image of the object. Which means that the image will resemble the object if the object was flipped in a vertical axis. Therefore, if an object is vertically symmetric the image formed will be the same as the object. Now, we must find the letters that have vertical symmetry.

                                

So, from the 26 letters A, H, I, M, O, T, U, V, W, X and Y are vertically symmetric. If we were to flip these images vertically from the centre, we would get the same letter. Other letters do not have such symmetry as shown in the figure.
Therefore, A, H, I, M, O, T, U, V, W, X, Y are the letters of English alphabet that will form identical images in a plane mirror. And due to the lack of vertical symmetry other remaining letters fail to form their identical image.

Note:
An image that can be obtained on the screen is called a real image and the image which can never be obtained on a screen is called a virtual image. The plain mirror and the convex mirror will form the virtual image. However, only concave mirrors can form the real image. An image formed by a plane mirror is formed by light rays from the object incident on the mirror. These rays do not intersect after reflection. The images formed in such a manner will always be virtual.