Question

The following  diagram shows the experimental set up for the determination of focal length of a lens using a plane mirror.

1. Draw two rays from the point O of the object to show the formation of image I at O itself.
2. What is the size of the image I?
3. State two more characteristics of the image I.
4. Name the distance of the objects O from the optical centre of the lens.
5. To what point will the rays return if the mirror is moved away from the lens by a distance equal to the focal length of the lens?

Answer 1

1. 
   
2. The size of the image will be the same as that of the object.
3. The image formed will be real and inverted.
4. The distance of object O from the optical lens will be equal to the focal length of the lens.
5. The position of the mirror from the lens does not affect the formation of the image as long as the rays from the lens fall normally on the plane mirror M.