Reflection of Light
Light is the common form of energy. It makes the objects visible to us. When you see an object you do so because light from the object enters in your eyes. Some objects such as sun, stars, burning candles, lamp, etc. which emit light by their own are called luminous objects.
Some other objects may bounce back a part of the light falling on them from any luminous object. This bouncing back of light after falling on any surface is called reflection of light.
When a beam of light comes in contact with an object, a part or all of it gets bounced back. This phenomenon is called reflection of light. Some objects having smooth and shiny surface reflect better than others. A smooth shining surface, which reflects most of the light incident on it, is called a mirror.
Greek mathematician Euclid explained how light is reflected. The phenomenon of reflection was translated into laws by an Arabian scientist Alhazan in about 1100 A.D.
The direction of propagation of light, a beam of light consists of number of rays. The incident ray is the ray of light falling on the reflecting surface. The normal is the line drawn at 90° to the surface at the point where the incident ray strikes the surface.
The light coming back from the reflecting surface is called reflected ray. The angle of incidence is the angle between incident ray and normal and angle of reflection is the angle between reflected ray and normal.