Question

A normal eye is not able to see objects closer than 25 cm because :

• A. The focal length of the eye is 25 cm
• B. The distance of the retina from the eye-lens is 25 cm
• C. The eye is not able to decrease the distance between the eye lens and 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

A normal eye is not able to see objects closer than 25 cm because the eye is not able to decrease the focal length beyond a limit since ciliary muscle are most strained, beyond that they do not strain. So, the focal length cannot be less than that. So, the eye cannot see objects clearly, for a distance less than 25 cm.