Polarisation

• What type of waves make up the EM spectrum?

  Transverse
• What can be said about the speed of EM waves in a vacuum?

  They all travel at the same speed of

  $3 ×10^8$
• Describe the structure of EM waves

  An alternating magnetic field that oscillates perpendicular to an alternating electric field, both of which oscillate perpendicular to the direction of travel
• What is polarisation?

  When the oscillations of the are limited to a single plane
• What happens when 2 polarising filters are rotated relative to eachother?

  When they are aligned, there is light clearly seen

  When they are rotated through 90 degrees, the intensity decrease to 0