5.3.5 visible light

• There are seven colours in the visible light spectrum

  • red
  • orange
  • yellow
  • green
  • blue
  • indigo
  • violet
• Uses of visible light

  • see the world around us
  • fibre optics
• We use visible light in fibre optics because it can be totally internally reflected. This means we can transmit signals along optical fibres without signals getting lost
• In a triangular prism, red light’s speed changes the least in the prism, so its direction changes the least.
• Opaque

  • either reflect or absorb all light that hits them
  • no light passes through
• Translucent

  • transmit light but the rays are scattered
  • cannot see objects clearly through translucent objects
• Transparent

  • transmit light without scattering the rays
  • can clearly see objects on the other side of the transparent object
• Opaque objects either reflect or absorb all light that hits them.
• When light hits can object it can be

  • reflected
  • refracted
  • absorbed
  • transmitted