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What is the power of normal eye lens?

A normal eye can see objects from 25cm (near point) till infinity (far point).

So, we take:

Object distance, u = -∞ (- infinity)

Image distance, v = 25 cm

By using lens formula, we get,

1/v - 1/u = 1/f

1/25 - 1/-∞ = 1/f

1/f = 1/25 + 0           [Since, 1/-∞ = 0]

1/f = 1/25

f = 25 cm

For determining the power of the lens, focal length should be in metres.

Therefore, 25/100 = 0.25 m

Power, P = 1/f

P = 1 / 0.25

P = 4 D

Therefore, the power of a normal eye is 4 Dioptres.

Hope this helps u...........

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 You could be 20/20 uncorrected with a prescription anywhere from +3.00 to -0.50 or so.

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 25D is power of normal eye .

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For someone with 20/20 UNcorrected? Even then, I'm not sure what would be "normal". You could be 20/20 uncorrected with a prescription anywhere from +3.00 to -0.50 or so.

 

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4  is the power of normal eye lens..

since the near point of eye is 25 cm.therefore focal length =25 cm..

power=1/0.25(focal length is taken in metre)

           =100/25

            =4 diopetre

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+4D

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4D

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