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Parts of an Eye

A person uses...

Question

A person uses concave lenses, if he sees after removing its spectacles, then in his eyes image ofthe object will be formed

A

Behind retina

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B

On fovea centralis

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C

In front of retina

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D

Far from retina

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Solution

The correct option is C In front of retina
The lens capsule is attached to the ciliary body by a ligament and serves to refract and focus light rays on retina and fovea centralis. This makes option B incorrect as if the image is focused on fovea centralis, the person would not need to wear lens. The convex lens bends the light rays and help focus the image on the retina which was otherwise being focused behind the retina or far from the retina by a less flexible lens or shortened eye ball; options A and D are incorrect. If the image was being focused in front of retina, as is the condition in myopia caused by elongated eyeball, the person would need a concave lens to diverge the light rays and thereby focus the image on the retina. This makes option C correct.

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Q. A person wears a pair of spectacles with a concave lens of power -2D. Find the farthest point to which he can see objects distinctly without his spectacles.

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