Refraction of Light Waves

Introduction

• Refraction: Change in direction of waves as they move from one medium to another (e.g., air to glass).
• Key Concepts:
  • Wave speed varies in different materials due to density differences.
  • Higher density = slower wave speed.

Behavior of Light Waves

• Traveling Perpendicular:
  • If waves hit the boundary at a 90-degree angle, they continue straight.
• Traveling at an Angle:
  • When hitting at an angle, waves refract (change direction).
  • Moving into a denser medium (e.g., air to glass) causes bending towards the normal (perpendicular line).

Drawing Ray Diagrams

• Basic Steps:

  1. Draw the normal at the point of incidence (where light hits the surface).
  2. Draw the incident ray and predict the refracted path.
  3. Refracted ray bends towards the normal in a denser medium.
  4. Continue the refracted ray to the opposite side of the medium.
  5. Draw the emergent ray as the light exits to a less dense medium, bending away from the normal.

• Angles:

  • Include angle of incidence and angle of refraction in diagrams.

Wave Speed and Wavelength

• Wave Speed Equation: Speed = Frequency x Wavelength.
  • Frequency remains constant.
  • Only wavelength changes with speed.
  • Increased speed = increased wavelength, and vice versa.

Triangular Prisms and Light Dispersion

• Different wavelengths refract at different angles.
• White light passing through a prism disperses into a spectrum (rainbow effect).

Conclusion

• Understanding refraction involves recognizing how light behaves at boundaries between different media.
• Important for predicting path changes and understanding light dispersion.