Question
Why is a normal eye not able to see clearly the objects placed closer than $25 \ cm$?
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Answer
- For seeing nearby objects, the ciliary muscles contract to make the eye lens thicker near the middle, so as to reduce the focal length of the eye lens.
- But ciliary muscles cannot be contracted beyond a certain limit and hence we cannot see clearly the objects closer than $25 \ cm$ from the eye.
- In other words, a normal eye is not able to see clearly the objects placed closer than $25 \ cm$ because all its power of accommodation has already been exhausted.
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