Lecture Notes: Refraction and Ray Diagrams

Introduction to Refraction

• Refraction occurs when waves change direction due to a change in speed.
• This typically happens when waves move from one medium to another.

Key Concepts

• Ray Diagrams: Visual tools to show the refraction of light.
  • Example: Light entering a glass block from the air.
  • Velocity Decrease: Light slows down in glass, bending towards the normal.
  • Velocity Increase: Light speeds up as it exits the glass, bending away from the normal.
• Direction Change: The apparent shift in the object's position due to refraction.
• Exception: No change in direction if waves enter/leave perpendicular to the surface (along the normal).

Wavefront Diagrams (Higher Tier Concept)

• Wavefront: Imaginary line connecting identical points (e.g., peaks or troughs) in waves.
  • Applies to both transverse and longitudinal waves.
  • Helps visualize collective wave movement.
• Refraction in Wavefront Diagrams:
  • As wavefronts move into a denser medium (e.g., glass), they slow down, shortening wavelength and bending towards the normal.
  • If wavefronts approach along the normal, they slow uniformly, resulting in no direction change.

Additional Resources

• Refraction exercises and questions are available in the Vision Workbook.

[Music] cues signify transitions and end of lecture.