Law of Reflection/Refraction + Total Internal Reflection

• Where light is reflected off a surface at the same angle

  • Incident ray - incoming ray of light
  • Normal - dotted imaginary middle light (forms a right angle with the surface)
  • Angle of incidence - the angle an incoming ray makes with the normal
  • angle of reflection - the angle a reflected ray makes with the normal
• Angle of incidence = Angle of reflection
• Refraction

  • the bending of light as it passes through different substances
  • The bending of light rays is caused by the speeding up or slowing down of light as it moves from one substance to another
• The different substances that affect the refraction of light are called mediums, such as air, glass or water.
• Light that moves at an angle from a less dense to more dense medium bends towards the normal.
• Light that moves at an angle from a more dense to a less dense medium bends away from the normal.
• Light that moves straight on from one medium to another does not bend. It is not refracted.
• Total Internal Reflection:

  • where light travels from a more dense substance into a less dense substance and reflects instead of refracting.
  • Angle of incidence must be greater than the critical angle to reflect
  • Light is unable to escape from the substance ( reflected along the medium)