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Question

A concave lens is used in :

A

a simple camera

B

spectacles for the correction of short sightedness

C

a magnifying glass

D

vehicles to see objects on rear side

Easy

Solution

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Correct option is
B

spectacles for the correction of short sightedness

Answer is B.

Myopia or shortsightedness occurs when light is focused in front of the retina. It occurs because either the eyeball is too long, or because the cornea is too curved. Despite maximum flattening of the lens, the eye is not able to focus the light rays further back, and on to the retina.
Concave lenses (called minus lenses) are used to bend light rays slightly outwards. The light rays then have a greater angle to bend back to focus when travelling through the cornea and lens. As a result, the light rays focus further back on the retina. 
Hence, concave lenses are used in spectacles for the correction of short sightedness.

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