Question

A normal eye is not able to see object closer than $25\text{cm}$ because,

• A. the focal length of the eye is $25\text{cm}.$
• B. the distance of the retina from the eye lens is $25\text{cm}.$
  
• C. the eye is not able to decrease the distance between the eye-lens and the retina beyond a limit.
  
• D. the eye is not able to decrease the focal length beyond a limit.

Answer 1

The correct option is D the eye is not able to decrease the focal length beyond a limit.

When the eye is focused on a closer object, the ciliary muscles are strained and the focal length of the eye-lens decreases. Because of some reason, the eye is not able to decrease the focal length beyond a limit, hence a normal eye is not able to see objects closer than $25\text{cm}$.