Refraction

• • The bending or change in direction of light when it travels from one medium to another. Each medium has its own index of refraction
• What causes refraction

  • Normally light travels in straight lines as long as the light is traveling through the same material
  • Refraction is due to changes in the speed of light. Different media slow down light by different amounts
  • The more that light slows down, the more the light is refracted
• Less to More Dense

  • When light travels from a less dense medium into a denser medium, light will slow down
  • Slowing down causes the light ray to bend towards the normal
  • Results in the angle of incidence being greater than the angle of refraction
• More to less Dense: Water to Air

  • When light travels from a more dense medium to less dense medium, the light will speed up
  • Light speeding up causes the light ray to bend away from the normal
  • Results in angle of refraction becoming greater than the angle of incidence
• Speed of Light

  • Speed of light in vacuum: c=3.00x10^8m/s
  • Speed of light in a medium (v) is different for different materials
• Index of refraction

  • The index of refraction for a medium is determined by comparing the speed of light in the medium with the speed of light in a vacuum
• Index of refraction of material = speed of light in vacuum/speed of light in medium

  • N = index of refraction
  • C = speed of light    
  • V = speed of light in given medium