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

6. EXAMPLES
Example 1:
Find the angle of reflection

7. Examples
Example 2:
Find the angle of reflection

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