A small hole P is made in a piece of cardboard

A small hole P is made in a piece of cardboard. The hole is illuminated by a torch as shown in Figure. The pencil of light coming out of the hole falls on a mirror.

 

At which point should the eye be placed so that the hole can be seen?

  1. A
  2. B
  3. C
  4. D

Answer

Eye should be placed at A because the hole can be seen only when the angle of incidence is equal to the angle of reflection.

The correct option is A.