Question

A person, whose eye has a lens-to-retina distance of 2.0 cm, can only clearly see objects that are closer than 1.0 m away. what is the strength

Answer 1

To calculate the strength of the eye lens, we use the formula

`(P)/(100) = (1)/(f) =(1)/(u) +(1)/(v)` ( thin lens formula)

Here, u is the object distance and v is image distance.

Given,
`u =1 m=100cm` and
`v = 2 cm`

Therefore,

`(1)/(f) =(1)/(100) + (1)/(2)`

`(1)/(f) = 0.01 + 0.5`
`= 0.51 cm`

Thus, strength of the eye lens is

`P= (100)/(f) =(100)/((1)/(0.51) ) = 51 D`