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Question
A normal eye is not able to see objects closer than 25 cm because
Options
the focal length of the eye is 25 cm
the distance of the retina from the eye-lens is 25 cm
the eye is not able to decrease the distance between the eye-lens and the retina beyond a limit
the eye is not able to decrease the focal length beyond a limit.
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Solution
the eye is not able to decrease the focal length beyond a limit
The ciliary muscles adjust the focal length to form an image on the retina, but the muscles cannot be strained beyond a limit. Hence, if the object is brought too close to the eye, the focal length cannot be adjusted to form the image on the retina.
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