Light waves

• Light transmission through glass

  • light transmits through glass over long distances with very little absorption of the light
  • light reflects of the internal surface of the glass when glass bends to get around obstacles
• Fibre optic cables transmit information through infared and visible light. Shorter wavelengths allow more information to be carried.
• How are X-rays produced?

  In a tube with fast moving electrons that hit a metal target. They are then directed at a patient and it passes through their body.
• How does an X-ray tube work?

  • X-ray tube emits X-ray
  • X-rays pass through soft tissue but are absorbed by bones
  • A film or X-ray detector behind the object will detect the X-rays
  • The areas with no X-rays appear as different
• What are the three primary colours of light?

  Red, green and blue
• What are the three secondary colours of lights?

  Magenta (red + blue), yellow (red + green), cyan (blue + green)
• A colour filter will only allow certain wavelengths of light through.
• If no light is reflected, an object appears as black.
• If an object appears as white, all light is reflected
• The colour of an object (except white and black) is determined by the wavelength it reflects.