Image Formation by Spherical Mirror



Image formation by spherical mirrors

Concave mirrorObject positionImage positionImage sizeImage nature
1InfinityFocusPoint-sizedReal, inverted
2Beyond CBetween C and FDiminishedReal, inverted
3At CAt CSame sizeReal, inverted
4Between C and FBeyond CMagnifiedReal, inverted
5At FinfinityHighly magnifiedReal, inverted
6Between F and PBehind the mirrorMagnifiedVirtual, erect
For convex mirror, image is always formed behind the mirror, virtual, erect and diminished.


Uses of spherical mirrors

Spherical mirrors has various applications. Some applications of convex mirror are sunglasses, rear view mirrors, shaving mirror,etc. Some applications of concave mirrors are reflectors, converging of light, solar cooker etc. 


Laws of reflection

In the diagram, the ray of light approaching the mirror is known as the incident ray. The ray of light that leaves the mirror is known as the reflected ray. At the point of incidence where the ray strikes the mirror, a line can be drawn perpendicular to the surface of the mirror. This line is known as a normal line.
The normal line divides the angle between the incident ray and the reflected ray into two equal angles. The angle between the incident ray and the normal is known as the angle of incidence. The angle between the reflected ray and the normal is known as the angle of reflection. The laws of reflection are as follows:

  • The incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane.
  • The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal.
  • The reflected ray and the incident ray are on the opposite sides of the normal.


Image Formation from Spherical Reflecting Surfaces

The curved shining surface of a spoon acts as a mirror. The inner surface of a spoon acts like a concave mirror, while its outer surface acts like a convex mirror.Hence the inner surface of spoon shows inverted image and outer shows erect.