A person can focus objects clearly only between 15 cm and 40 cm.

[greg_k92]

Homework Statement

A person can focus objects clearly only between 15 cm and 40 cm. What eyeglasses would you prescribe

Homework Equations

1/p+1/q=1/f
P=1/f

The Attempt at a Solution

I don't really know what to use for p, or f

 

[rude man]

Did they teach you about the eye?
q = distance from eye lens to retina
p = distance from object viewed to eye lens

Now think - you want the person to see things at p = infinity but you also want them to focus as close-in as possible, given their innate limitation (uncorrected, p = 15cm to p = 40 cm).