Homework - Vision

  1. What does the word refraction mean?
  2. What is the normal to a surface?
  3. What is meant by the angle of incidence? Draw a diagram to illustrate.
  4. What is meant by the angle of refraction?
  5. Draw a diagram which shows a ray of light incident (from air) on a flat glass block with an incidence angle of 15 degrees. Complete the diagram to show the ray inside the block and suggest a possible angle of refraction.
  6. Draw a convex lens and show its effect on parallel rays.
  7. What does the word focus mean in optics?
  8. What is the meaning of the focal length of a lens?
  9. Draw a concave lens and show its effect on parallel rays.
  10. Copy and complete: When a ray of light in air enters glass it bends _____ the normal. When it leaves the glass it bends _____ the normal.
  11. What is the function of the iris, retina, pupil, lens and optic nerve in an eye?
  12. Draw a labelled ray diagram to show how an inverted image is formed on the retina of the eye.
  13. What does the word accommodation mean?
  14. Draw two diagrams, one which shows the eye focused on a nearby object, the other on a far object (exaggerate the difference in the shape of the lens and show the difference in the incident rays)
  15. A person is long sighted. Where will the rays from a nearby object be brought to a focus in relation to the retina? Can this person focus on nearby objects properly? What type of lens should be prescribed to correct this?
  16. State the formula for the power of a lens.
  17. State all the units which must be used for this formula to work correctly.
  18. Draw a diagram showing total internal reflection.
  19. Explain the term critical angle.
  20. What is a fibrescope (or endoscope)?
  21. What physical principle does the endoscope rely upon?
  22. Draw a diagram to show the important features of a medical endoscope.

Optional Questions - Research

  1. What is a coherent fibre bundle (as applied to fibrescopes)?
  2. What is meant by the polarisation of light?
  3. What is the refractive index of a material?
  4. What is Snell's law of refraction?