When a ray of light falls on a surface, then it can undergo one of the following three phenomenon reflection, refraction or absorption. When it falls on a normal surface then most of the light gets absorbed. So mirrors are polished surfaces coated with mercury such that they reflect most of the light falling on them. Now based on the type of reflecting surface we can classify mirrors as concave, convex or plane mirror. Here we will be talking about plane mirror only. So two form an image we require at least two rays from the object which meet or appear to meet at a point. In case of the plane mirror, here we have used three images for better clarity in the ray diagram shown below.
For the ray starting from point A and traveling in horizontal direction towards point E, the angle of incidence is 0 and hence it retraces its path. Similarly the ray starting from A and travelling towards point C, follows law of reflection. When these rays are produced backward they appear to meet at a point E and D. Now this image is known as virtual image. What is the difference between real and virtual image? In real image the rays of light actually meet after reflection while in virtual image it appears to meet but not actually meet. Real image can be obtained on screen but not virtual image.
Characteristics of the image formed by a plane mirror :
- It is virtual
- It is erect and of same size as the object
- The distance of object from the plane mirror is same as the distance of image from the plabe mirror.
One of the important characteristic of the image is that it is laterally inverted. It means if you raise your left hand it would appear in the plane mirror that you have raised your right hand.
Stay tuned with BYJU’S to learn about application of different type of mirrors, spherical mirrors, lenses etc. Watch this video to understand the significance of mirror formula which is also applicable to plane mirror.