1. Take a rubber ball and cut a portion of it with knife as shown in figure. Be careful. Ask your teacher to help you in cutting the ball).
2. The inner surface of the cut piece of ball is called concave surface and the outer surface of it is called convex surface.
3. If the reflecting surface of a mirror is concave, it is called a concave mirror see figure (a)
4. If the reflecting surface is convex, then it is called as convex mirror.
See figure (b).
5. Any concave or convex mirror is a part of a sphere. Hence these mirrors are called spherical mirrors.
