Refraction

• Basic steps of the practical.

  1. Draw around the block on a piece of paper, remove the block then draw a line normal to one of the sides.
  2. Draw three guide lines of incident at different angles to the normal, place the block on the page and shine the ray through your chosen guideline.
  3. Mark the incoming, and any outgoing rays of light with crosses.
  4. Turn lights on and measure the angles of reflection and refraction with a protractor and repeat for the other angles of incidence.
• What tool should be used to help draw the normal line on the sheet of paper?

  A set square or protractor to ensure that the angle is at a right angle to the main line.
• What is the purpose of drawing guidelines for the incident rays?


  You can shine the ray at the exact angles you want it without having to measure angles in the low light. It also reduces the length of time that the ray box needs to be on for since the incident angles are already measured.
• What precautions should be taken to use the ray box safely?

  Don’t touch any metal part since the box gets very hot when in operation, switch off when not in use to prevent overheating.
• What conditions are needed for this experiment?

  Low lighting is needed so that the rays are visible, all bags and equipment should be moved out of the way to reduce the likelihood of tripping due to poor visibility.
• Which angle is the angle of incidence?

  The angle as measured between the incident (incoming) ray and the normal.
• Which angle is the angle of reflection?

  The angle as measured between the reflected ray and the normal.
• What do you expect to find about the angle of incidence and the angel of reflection?

  The angle of incidence should be the same as the angle of reflection.
• What do you expect to find about the angle of refraction for different materials?

  It should be different for each material depending on its refractive index.