• Support PF! Buy your school textbooks, materials and every day products Here!

Help with optics problem involving diopters

  • #1
4
0

Homework Statement


A nearsighted man uses his ideally prescribed contact lenses that have a refractive power of −3.60 diopters. He would like a prescription for eyeglasses. What is the correct eyeglasses prescription if he wears his eyeglasses a distance of 2.30 cm from his eyes?

Homework Equations


I used the mirror equation. 1/f = 1/do + 1/di

The Attempt at a Solution


I found a solution to be -3.32 and what I did was convert the refraction power to focus and then convert it to centimeters and added 2.3 and then did the inverse of that to obtain -3.32 and apparently that is wrong. I have used chegg and they show the same exact method I employed. I don't understand. Help!
 

Answers and Replies

  • #2
rude man
Homework Helper
Insights Author
Gold Member
7,584
691
If his contact lenses are "ideally prescribed" I take that to mean perfect vision at infinity. So does it matter what the refractive power of the contacts is?
 
  • #3
4
0
If his contact lenses are "ideally prescribed" I take that to mean perfect vision at infinity. So does it matter what the refractive power of the contacts is?
I figured it out. I had to subtract 0.278 m - 0.023 m instead of adding. The correct answer was -3.92
 
  • #4
rude man
Homework Helper
Insights Author
Gold Member
7,584
691
I figured it out. I had to subtract 0.278 m - 0.023 m instead of adding. The correct answer was -3.92
OK, I misread the problem anyway ...
 

Related Threads for: Help with optics problem involving diopters

Replies
0
Views
2K
Replies
7
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
4
Views
3K
Replies
1
Views
347
  • Last Post
Replies
10
Views
4K
Top