reflection

• waves aren't always _________

  reflected
• name the three things that happen when a wave arrives at a boundary between 2 materials

  • the wave might be absorbed by the material, so the energy from the wave is transferred into that materials energy stores
  • the wave might be transmitted, this is where the wave enters the material but carries on travelling so it passes out to the other side. this often leads to refraction.
  • the wave could be reflected off the surface so it never even enters the material.
• what determines the way the wave travels when arriving at a boundary?

  • the wavelength
  • the properties of the two materials
• what diagram do we use to show reflection taking place?

  ray diagrams
• what is the rule of ray diagrams?

  the angle of incidence is always equal to the angle of reflection
• what is specular refection? give an example:

  specular reflection is a clear image e.g. a mirror

  • a mirror is perfectly smooth and the boundary is completely flat.
  • this means all the normals are in the exact same direction
  • all the incoming light rays will be reflected in the same direction
• what is diffuse/scattered reflection? give an example:

  diffuse/scattered reflection is when we usually cant see our reflection at all e.g. paper

  • paper has a rough surface which means the boundary is all bumpy
  • even though the incoming light rays are all coming down in the same direction, the normals will all be shooting off in different directions. this is because the surface itself isn't flat.
  • this means the light will be reflected in all different directions