05 – The Law Of Reflection

1. 05 – The Law Of Reflection

2. What happens when waves hit a boundary? • When water waves strike a barrier straight on, they reflect back along the same path.

3. What happens when waves hit a boundary? • When incident waves strike a parabolic surface, the waves reflect to a focal point.

4. What happens when waves hit a boundary at an angle? • When incident waves strike a barrier at an angle they reflect off at the same angle. • The Normal (N)is a line drawn perpendicular to the barrier/surface the wave hits. The normal line intersects the surface at the identical point the wave hits the barrier/surface. • The Angle of Incidence,θi , of a wave is the angle measured from the incident wave (i) to a line normal to the barrier/surface. • The Angle of Reflection, θr , of a wave is the angle measured between the reflected wave (r) and a line normal to the barrier/surface.

5. The Angle of Incidence is equal to the Angle of Reflection The Law of Reflection

6. Example 1: • Find the angle of reflection EXAMPLES

7. Example 2: • Find the angle of reflection Examples

8. Example 3: • Determine which surface in the diagram the wave reflects from last and find the angle of reflection from that surface. Examples