Problem

A person decides to use an old pair of eyeglasses…

Problem 38 Easy Difficulty

An elderly sailor is shipwrecked on a desert island, but manages to save his eyeglasses. The lens for one eye has a power of $+1.20$ diopters, and the other lens has a power of $+9.00$ diopters. (a) What is the magnifying power of the telescope he can construct with these lenses? (b) How far apart are the lenses when the telescope is adjusted for minimum eyestrain?

Answer

a. 7.50
b. 0.944 m

Topics

Electromagnetic Waves

Wave Optics

Book Cover for College Physics 2017

College Physics 2017

Chapter 25

Optical Instruments

Discussion

You must be signed in to discuss.

Top Physics 103 Educators

Christina K.

Rutgers, The State University of New Jersey

Farnaz M.

Other Schools

Zachary M.

Hope College

Jared E.

University of Winnipeg

Watch More Solved Questions in Chapter 25

Problem 1

Problem 2

Problem 3

Problem 4

Problem 5

Problem 6

Problem 7

Problem 8

Problem 9

Problem 10

Problem 11

Problem 12

Problem 13

Problem 14

Problem 15

Problem 16

Problem 17

Problem 18

Problem 19

Problem 20

Problem 21

Problem 22

Problem 23

Problem 24

Problem 25

Problem 26

Problem 27

Problem 28

Problem 29

Problem 30

Problem 31

Problem 32

Problem 33

Problem 34

Problem 35

Problem 36

Problem 37

Problem 38

Problem 39

Problem 40

Problem 41

Problem 42

Problem 43

Problem 44

Problem 45

Problem 46

Problem 47

Problem 48

Problem 49

Problem 50

Problem 51

Problem 52

Problem 53

Problem 54

Problem 55

Problem 56

Problem 57

Problem 58

Problem 59

Problem 60

Problem 61

Problem 62

Problem 63

Problem 64

Problem 65

Problem 66

Problem 67

Video Transcript

So in this problem, the person has two lenses of different powers. One is positive, 1.2 doctors and the other one is positive. Nine doctors. So from here, we can actually find the focal length of both of the lenses, which is basically the reciprocal of the power of each. And I have already shown the focal length F one enough to hear. So if one is going to be a zero point 833 0.833 meter and after is going to be 0.111 meter. So if the sailor wants to be like telescope, that actually f one has to be the focal length of the objective. Okay. Hey, 33 and F two has to be the focal length of the eyepiece. Now, from here, we can easily find the magnification for party. So far, for part a, the magnification of the angular magnification of the telescope is for collective objective. Over focal length off eyepiece. This is going to be a 0.833 over 0.111 And this will give me a 7.5. All right now for part B the length of the telescope basically would be the focal length of the objective and focal length of the I Piss, which is 0.833 plus 0.111 meters because 0.944 meters.

Netra S.

University of Wisconsin - Milwaukee

Topics

Electromagnetic Waves

Wave Optics

Book Cover for College Physics 2017

College Physics 2017

Chapter 25

Optical Instruments

Top Physics 103 Educators

Christina K.

Rutgers, The State University of New Jersey

Farnaz M.

Other Schools

Zachary M.

Hope College

Jared E.

University of Winnipeg