The diameter of the eye ball of a normal eye is about 2.5cm. The power of the eye lens varies from
The diameter of the eye ball of a normal eye is about 2.5cm. The power of the eye lens varies from
A. 9D to 8D
B. 40D to 32D
C. 44D to 40D
D. None of these
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Correct Answer - C
An eye see distant objects with full releaxtion.
So, `(1)/(2.5xx10^(-2))-(1)/(-oo)=(1)/(f)`
or `P=(1)/(f)=(1)/(2.5xx10^(-2)=40D`
An eye see an object at 25cm with strain
`(1)/(2.5xx10^(-2))-(1)/(25xx10^(-2))=(1)/(f)`
`therefore P=(1)/(f)=40+4=44D`
The power of the eye lens various from 44D to 40D.
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