The far point of a myopic eye is 60 cm . What is the nature and power of lens required to correct the problem?
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myopia means shortsightedness. The person is not able to focus properly on distances more than 60 cm. But he /she is able to focus properly up to 60cm.
the way of correcting this will be to create a virtual image of distant objects (more than 60cm) at 60 cm from the eye. Let us take an object very far from the eye.
Hence, u = -infinity. v = -60 cm. f = ?
1/v - 1/u = 1/f
f = -60 cm. So the lens is a concave lens or diverging lens. of focal length 60cm or 0.60 meter.
power of lens is = 1 meter / (-0.60 meter) = - 1.667 Dioptres
the way of correcting this will be to create a virtual image of distant objects (more than 60cm) at 60 cm from the eye. Let us take an object very far from the eye.
Hence, u = -infinity. v = -60 cm. f = ?
1/v - 1/u = 1/f
f = -60 cm. So the lens is a concave lens or diverging lens. of focal length 60cm or 0.60 meter.
power of lens is = 1 meter / (-0.60 meter) = - 1.667 Dioptres
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