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 happens when a wave arrives at a boundary?

  It can be absorbed, transmitted, or reflected
• What occurs when a wave 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 is the key rule for reflection?

  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
• How do you measure the angle of incidence?

  Measure the angle between the incoming ray and the normal
• What is the point where the incoming ray touches the boundary called?

  The point of incidence
• What characterizes specular reflection?

  All incoming rays are reflected in the same direction
• What type of surface causes diffuse reflection?

  A relatively rough surface
• How do normals behave on a rough surface?

  Normals point in different directions
• Why can't you see your reflection in paper?

  It undergoes diffuse reflection
• What is true for both specular and diffuse reflection?

  The angle of incidence equals the angle of reflection
• What is the relationship between the angle of incidence and the angle of reflection?

  They are always equal
• What happens to reflected rays from a rough surface?

  They get scattered in different 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. Label the point of incidence.