# Homework Help: A farsighted man with eyeglasses problem

1. Mar 26, 2012

### KendrickLamar

1. The problem statement, all variables and given/known data
A farsighted man uses eyeglasses with a refractive power of 2.20 diopters. Wearing the glasses 0.03 m from his eyes, he is able to read books held no closer than 0.28 m from his eyes. He would like a prescription for contact lenses to serve the same purpose. What is the correct contact lens prescription, in diopters?

2. Relevant equations
1/do + 1/di = 1/f

3. The attempt at a solution
well starting off i figured if the power is +2.20 dipoeters then the fd is going to be -1/2.20
not sure but since with the glasses it would be 1/fd-.03? and then with the contacts what would happen since there no distance? im just really confused now lol

2. Mar 26, 2012

### KendrickLamar

500 views no replies? any ideas?? anyone lol!?

3. Mar 27, 2012

### ehild

Find out at what distance d from the eye the image forms with the ordinary eyeglasses when the book is held at 0.28 m from the eye. What should be the focal distance when the lens is on the eye and the distance of the image is equal to d in the same situation?

ehild

4. May 23, 2013

### wutiantai

Good glasses

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