Question

A normal eye is not table to see objects closer than $25$cm because.

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

Answer 1

The correct option is B The eye is not able to decrease the focal length of eye lens beyond a limit

Focal length of the eye lens is adjusted by changing its radius of curvature. This is performed by the ciliary muscles. Thus it can stretch or contract upto a certain limit only and hence the focal length cannot decrease beyond a limit .