# 7th Class Science Lights and Sound Formation of Image by plane Mirror

## Formation of Image by plane Mirror

Category : 7th Class

### Formation of Image by Plane Mirror

The picture of our face in the mirror is called image and our face is called object. The formation of our image in the mirror is possible due to the reflection of light. In the absence of light, the formation of image is not possible. If we put a mirror in front of our face in the dark (light is not available) we cannot see the image of the face. Light is therefore an important factor for the formation of image.

Images formed are of two types:

• Virtual image
• Real image

The image, which cannot be obtained on the screen is called virtual image. The image formation of our face in the plane mirror is virtual image.

The image, which is formed by the mirror by the actual intersection of rays of light is called real image. There are three types of mirror. These are, plane mirror, convex mirror, concave mirror.

Look at the following picture of a plane mirror and its image formation

Fig. (1) Plane mirror                                        Fig. (2) Image formation in a plane mirror

In the figure (1), a virtual image is formed by a plane mirror. In the figure (2), formation of a virtual image by a plane mirror is shown. An object (0) is placed in front of the mirror. Incident ray falls from 0 and get reflected by the mirror. The reflected rays are produced backward and they meet at the point /. The observer receives the reflected rays and image as shown at /. The image of the object is not the actual intersection of light and therefore is called virtual image. The incident ray falls on the plane mirror by 90° retraces its path or reflected through the same path. An incident ray falling on the plane mirror by 6 is reflected by the same angle (9).

The image is formed by a plane mirror is due to the reflection of light. Why an image is called virtual when it is formed by a plane mirror?

(a) It can be obtained on the screen

(b) It cannot be obtained on the screen

(c) Real image is formed

(d) All of these

(e) None of these

The image, which is formed by a plane mirror is due to the reflection of light. At which one of the following point images of an object is formed?

(a) Imaginary meeting point of reflected rays

(b) Imaginary meeting point of incidence rays

(c) At the meeting point of both the rays

(d) All of these

(e) None of these