Calculating the Angular Size of an Image with a Magnifying Glass

Click For Summary

Homework Help Overview

The discussion revolves around calculating the angular size of an image viewed through a magnifying glass, given specific parameters such as the near point of the eye, the angular size of the object, and the focal length of the magnifying glass.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the relationship between angular size and linear dimensions, questioning how to derive the necessary distances and sizes from the given information. There is an emphasis on using ray diagrams for clarification.

Discussion Status

Some participants have provided insights on the relationships between the heights and distances of the object and image, while others highlight the importance of the object's position relative to the eye for clarity. Multiple interpretations of the problem setup are being discussed.

Contextual Notes

Participants note the limitations of the eye's accommodation and the necessity of using a magnifying glass to enhance the angular size for better visibility. The specific values for distances and angular sizes are critical to the discussion but are not fully resolved.

kbray278
Messages
2
Reaction score
0

Homework Statement



The near point of a naked eye is 33 cm. When an object is placed at the near point and viewed by the naked eye, it has an angular size of 0.060 rad. A magnifying glass has a focal length of 16 cm, and is held next to the eye. The enlarged image that is seen is located 51 cm from the magnifying glass. Determine the angular size of the image.


Homework Equations


Angular size=Theta(i)/Theta(o)


The Attempt at a Solution



Wasn't sure what to do
 
Physics news on Phys.org
angular size of the object αo = h/33. The angular size is given. Find the linear size h of the object.
Focal length of the glass and the image distance from the magnifying glass is given. From that find the object distance so
The angular size of the image = h/so.
 
rl.bhat said:
angular size of the object αo = h/33. The angular size is given. Find the linear size h of the object.
Focal length of the glass and the image distance from the magnifying glass is given. From that find the object distance so
The angular size of the image = h/so.

To clarify, height of image/distance of image (which you want to find) = height of object/distance of object. This can easily be seen with a ray diagram.
 
ideasrule said:
To clarify, height of image/distance of image (which you want to find) = height of object/distance of object. This can easily be seen with a ray diagram.
In this problem size of the image is irrelevant. You have to bring the object closer to the eye to make its angular size larger to see its details clearly. Because of the limitation of the accommodation of the eye, we cannot see the object clearly. To see the object in the same position, we have to use magnifying glass which forms its image at near point.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
8K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
1K
Replies
12
Views
9K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 1 ·
Replies
1
Views
4K