00:01
Problem 34 .54 is similar to example 34 .14.
00:11
That is example 34 .14.
00:18
And i'd strongly urge you to take a look at this example.
00:22
In this problem, we're told that a person sees clearly up close, but they can't focus on objects beyond 75 centimeters.
00:33
And that this person has decided to wear contacts to correct their vision.
00:40
In part a, they want to know if the person is near -sighted or far -sighted.
00:46
Well, since a person can see up close and they can't see beyond a certain distance, then they're near -sighted.
00:59
And in part b, they want to know if they should wear converging or diverging lenses to correct their vision.
01:08
In the subsection of chapter 34 that deals with the eye, we're told that a near -sided eye, or myopic eye, converges parallel bundles of rays so that an image can form properly on the retina, so it converges them too much.
01:27
Therefore, you need a diverging lens to fix this issue.
01:35
And now we're asked to find focal length in the power in diopters.
01:39
So we'll use.
01:41
Equation 34 .16 which tells us that one over s plus one over as prime is equal to 1 over f.
02:01
Now for the near -sided eye, you want to be able to see far, right? that's the idea...