How do you determine the image size formed by a convex lens?

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Homework Help Overview

The discussion revolves around determining the image size formed by a convex lens when a candle is placed at a specific distance from it. The focal length of the lens is also provided, leading to questions about image formation and size calculations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to use the lens formula to find the image distance and questions how to determine the object height needed for calculating the image size. Other participants note that without the object's height, a numerical answer for the image size cannot be provided.

Discussion Status

Participants are exploring the relationship between object height and image height, with some suggesting that the image height is directly related to the object height. There is a recognition that the lack of object height limits the ability to provide a numerical solution.

Contextual Notes

There is an assumption that the dimensions of the candle are necessary for calculating the image size, which has not been provided in the original problem statement.

kriegera
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Homework Statement


A candle is placed 10 inches from a convex lens whose focal length is 5 in. Where will the image be formed? How large an image is formed?



Homework Equations





The Attempt at a Solution


Here we use the following formula to find where the image will be formed:
1/f=1/Do+1/Di  1/Di=1/f-1/Do =
1/Di=1/5-1/10 = 2-1/10 = 10 in.


Here's the equation to solve part B but I don't know how to figure "So" which would be dimensions of the candle. Any help?

Si=So(Di/Do) =
Si=So(10/10) =
 
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Well you can't give a numerical answer but you can say that the image formed is the same height as the object.
 
AtticusFinch said:
Well you can't give a numerical answer but you can say that the image formed is the same height as the object.


So, there's no numerical way to solve without being given the height of the object?
 
kriegera said:
So, there's no numerical way to solve without being given the height of the object?

Nope, because that would mean that the image height does not depend on the object height which is clearly not true.
 

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