Thought provoking problems on optics


These problems are from pre-test conducted in teacher's workshops by Prof HC Verma and his team.

  1. Light of wavelength 500 nm is incident on a aperture of following size. What can be said about the validity of ray optics in each of the above cases?
    1. 100 times the wavelength
    2. 1000 times the wavelength
    3. 10 times the wavelength
  2. A parallel beam of light goes into a transparent box and returns. From the box the light comes as a divergent beam. Which the following are the possible optical instrument in the box? (a) A plane mirror (b) a concave mirror (c) a convex mirror.
  3. Interpret the graph given below. Here v and u are the image positions and object positions measured in metres for a lens/mirror. Identify the lens/mirror. Find the focal length of the lens/mirror from the graph. Mark regions which represent the real and virtual image as well as real and virtual object.

Your constructive comments