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Power of accommodation cannot reduce the focal length below a certain value because:
AThe cornea fully absorbs near light (option)
BThe retina is too far away
CLight has a maximum bending angle
DThe ciliary muscles have a maximum contraction limit and the lens has a maximum curvature
Answer & Solution
Correct answer: D. The ciliary muscles have a maximum contraction limit and the lens has a maximum curvature
1. Ciliary muscles can contract only so much; lens curvature has a physical limit.
2. Hence the lens cannot shorten its focal length indefinitely.
3. This sets the near point at about 25 cm for a normal young eye.
_Source: NCERT Class 10 Science, Ch 10 "The Human Eye and the Colourful World", §10.1.1_
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