physics light

• what kind of wave is light?

  transverse wave
• what are transverse waves caused by?

  vibrations which are perpedicular to the direction of wave travel
• what are specular reflections?

  when light is reflected of a smooth surface
• what is the ray going into the 'reflected area' called?

  incident ray
• what is the ray bouncing off the reflective surface called?

  reflected ray
• what is the angle of incidence 


  the ray going into the reflective surface which makes a angle going into the normal (centre line)
• what is angle of incidence always equal to?

  angle of reflection
• light getting reflected of a unsmooth surface?

  diffuse reflection
• how is speed decrease 


  if light travells through a different medium
• The higher the refractive index, the slower light travels through the material.
• in refraction, the speed of light is the same in all directions, but the speed of light in a material is slower than in a vacuum
• The angle of refraction is less than the angle of incidence
• The ray that exits the block is called the emergent ray. The emergent ray travels in the same direction as the initial incident ray.
• cornea 


  transparent layer at the front of the eye, some refraction of light occurs there
• retina


  contains cells that detect light and colour, sensitive to light and can be damaging
• Cornea


  Transparent layer at the front of the eye. Some refraction of light occurs here.
• Retina


  Contains cells that can detect light and colour. It is sensitive to light that is too bright and can be damaged.
• Lens


  Refracts light that passes through it. Muscles can change the shape of the lens so it can refract light by different amounts (depending on how far away an object is). The more a lens is curved, the more light will refract.
• Iris


  Coloured part of the eye around the pupil. Light does not pass through the iris.
• Pupil


  Dark area in the middle of the eye. Light passes through the pupil. The iris has muscles that can open or close the iris. When it is very bright, the iris will be mostly closed and only a small part of the pupil will be seen. This is to protect the retina from damage. When it is dark, the opposite happens. The iris will be mostly open to allow more light to reach the retina.
• Nerve


  Carries the signal from the retina to the brain.
• White light


  Made from different individual colours
• Passing white light through a prism

  1. Light is split up into seven different colours called a spectrum

  2. This splitting of the colours is called dispersion
• Dispersion is what causes rainbows
• Order of colours in the spectrum

  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Indigo
  • Violet
• ROY G. BIV


  Mnemonic to remember the order of colours in the spectrum
• Different colours of light

  Experience different refractive indices
• Violet


  Refracts most as it experiences the highest refractive index
• Red


  Refracts least as it experiences the lowest refractive index
• Phrase "violet bends most violently"


  Helps remember that violet refracts most
• Filter


  Only allows one colour of light to be transmitted through it, other colours are absorbed
• Filters


  • Red filter
  • Green filter
  • Violet filter
• Different objects look coloured because of the light that they reflect
• Green object


  Looks green because it reflects only green light into our eyes
• Red object


  Looks red because it reflects red light into our eyes
• White object


  Reflects all seven colours of light in the spectrum