Reflection of light(Exposition)

Reflection from surfaces

Light beams are reflected from surfaces according to the law of reflection, which states that the angle of incidence is equal to the angle of reflection.

Here an explanation of the law builds up, step by step. (Remember that rays are figments of your imagination.)

The angles of incidence (i) and reflection (r) are measured between the incident (incoming) and reflected (outgoing) rays and the normal line. The normal line is a construction line drawn perpendicular to the reflecting surface at the point where the incident ray strikes.

Predicting what will happen using ray diagrams

This ray diagram shows the formation of a shadow by an opaque thing. This might represent what happens when a narrow-beam torch forms the shadow of a book on a wall. This model represents the actual event in a number of ways:

When thinking about ray diagrams, it is important that you remember that they are a model: they predict what will happen, but do not show a photo-realistic imitation of the phenomenon.

In the case of this shadow, you might be able to make the following predictions: