5.4 Wave Behavior - Reflection

Seeing your reflection in the mirror each morning, or hearing echoes when you shout inside a cave should be evidence enough that waves such as light and sound are reflected. In fact, this is a property common to all waves.

The general rule for reflection is that the angle of incidence onto a reflective surface equals the angle of reflection for any ray or line representing a wave train, a one dimensional wave progression from a source. The angle of incidence can better be described as the angle that a ray makes with a line perpendicular to the surface of the material, called the normal. The normal, an imaginary line, is "drawn" at the point that a ray touches the surface. It is important that the incident ray be compared to this line, instead of the surface itself, simply because the surface of reflection may not be straight, even locally.

The visual effects of reflection will be discussed in Unit 8, Optics.