Refraction

• Refraction - when a wave enters a denser medium it causes it to bend toward the normal.
• Higher density of medium = Wave will slow down when it passes through medium.
• Lower density of medium = Wave will speed down when it passes through medium.
• If the wave hits the medium at 90 degrees (perpendicular) it will continue to go straight. However, if the wave hits the medium at an angle then it will be refracted.
• If the wave goes into a more dense medium, then the wave will bend towards the normal.
• If the wave goes into a less dense medium, then it will bend away from the normal.
• Ray diagram;

  A) Incident ray

  B) Refracted ray

  C) Emergent ray

  D) Point of incidence

  E) Normal

  F) Angle of incidence

  G) Angle of refraction

  
• Frequency stays the same during refraction (important for the wave speed equation).
• Different wavelengths of light (different colours) are refracted by different amounts. This means that if white light, which has all the colours, is passed through a triangular prism then each colour will bend at different degrees. This allows us to see the different colours in white light.