visible light

• • visible light has wavelengths from violet (400nm) to red (700nm)
• • the primary colours are red, green and blue
  • when put together, they make white light
• • opaque objects to not transmit light
  • when hit by light, they absorb some light and reflect some
• • white objects reflect all wavelengths of light equally
  • black objects obsrob all wavelengths of visible light
  • black is lack of visible light
• • transparent and translucent objects transmit light
  • they are transparent because light is transmitted with little absorption
• colour filters:

  • when white light passes through coloured filter, all colours absorbed expect for colour of filter
  • an object that appears blue in white light will appear black in red light
  • red light contains no blue light for object to reflect