Question

What power lens is needed to correct for farsightedness

wherethe uncorrrected near point is 75 cm?

Answer 1

To solve this problem we will apply the concept related to the lens power with which farsightedness can be corrected. Mathematically this value is given by the relationship,

`P = (1)/(f)`

Here,

f =focal length

In turn, said expression can be exposed in terms of the distance of the object and the image as:

`P = (1)/(p)+(1)/(q)`

Here,

p = Object Distance ( By convention is 25cm)

q = Image distance

Replacing we have,

`P = (1)/(0.25)+(1)/(-0.75)`

`P = +2.67D`

Therefore the power lens that is needed to correct for farsightedness is +2.67D