Reflection

• What is the focus of today's video?

  Reflection of waves off a boundary
• What are the two types of reflection discussed?

  Specular and diffuse reflection
• What can happen when a wave arrives at a boundary?

  It can be absorbed, transmitted, or reflected
• What happens to a wave when it is absorbed by a material?

  Energy is transferred to the material's stores
• What does it mean for a wave to be transmitted?

  The wave enters the material and continues traveling
• What leads to refraction when a wave is transmitted?

  The wave passes out the other side of the material
• What determines which of the three outcomes occurs when a wave meets a boundary?

  The wavelength of the wave and material properties
• What is the rule for drawing ray diagrams regarding angles?

  The angle of incidence equals the angle of reflection
• How do you start drawing a ray diagram?

  Begin with the boundary between two materials
• What does the normal line represent in a ray diagram?

  A dashed line perpendicular to the surface
• What is the angle of incidence in the example given?

  45 degrees
• What is the point where the incoming ray touches the boundary called?

  The point of incidence
• What type of reflection occurs with smooth materials like mirrors?

  Specular reflection
• Why do mirrors provide a clear image?

  All normals are in the same direction
• What happens to light rays on rough surfaces like paper?

  They are reflected in different directions
• Why can't you see your reflection in paper?

  It has a rough surface that scatters light
• What is true about the angle of incidence in both types of reflection?

  It is always equal to the angle of reflection
• How do normals behave on rough surfaces?

  They point in different directions
• What happens to reflected rays from a rough surface?

  They get scattered in various directions
• What are the steps to draw a ray diagram for reflection?

  1. Draw the boundary between materials.
  2. Draw the incoming ray with an arrow.
  3. Draw the normal line perpendicular to the surface.
  4. Measure the angle of incidence.
  5. Draw the reflected ray at the same angle as incidence.
  6. Mark the point of incidence.
• What are the differences between specular and diffuse reflection?

  • Specular Reflection:
  • Occurs on smooth surfaces
  • Produces clear images
  • Normals are aligned

  
  

  • Diffuse Reflection:
  • Occurs on rough surfaces
  • Produces scattered light
  • Normals point in different directions