Understanding Magnification in Lens Systems

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Homework Help Overview

The discussion revolves around a lens system used to produce a real image of a candle flame. The original poster seeks to determine the focal length of the lens and the magnification when the object distance is changed. The problem involves understanding the relationships between object distance, image distance, and magnification in lens systems.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to apply the magnification equation but encounters difficulties with the results. Some participants question the type of lens being used and suggest that a diagram with ray tracing would clarify the situation. Others note the importance of considering the sign of the magnification due to the image being inverted.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the sign of the magnification, and there is an acknowledgment of potential errors in the original poster's calculations. The original poster has also made efforts to clarify their explanation and provide additional context.

Contextual Notes

The original poster mentions issues with attachments and diagram clarity, which may affect the understanding of the problem setup. There is also a reference to the wording of the homework question, indicating a focus on accuracy in problem representation.

Phoenixtears
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GREEN= Correct

Homework Statement


The lens in the figure is used to produce a real image of a candle flame at the 36 cm mark. What is the focal length of the lens?
focal length= 9


(My attachments aren't working, however, if you were to draw a line, put a lens in the middle, then a small candle on the left and a magnified, inverted candle on the left, that's the drawing. The length from the object from the small candle to the lens is 12cm at first, and the length from the lens to the larger image of the candle is 36 at first, the changed lengths are mentioned below. I'm so sorry about this).

Change the location of the object to 11 cm. Determine the location and magnification of the image.

location= 49.5
magnification=____

Homework Equations



h'/h= s'/s= magnification

In other words: the ratio of height of object to height of image equals the ratio of length to lens for the object to the length to lens of the image, which equals magnification.

The Attempt at a Solution



I don't understand why the magnification problem isn't panning out. I'm using the equation above, stating that the image distance over the object distance equals the magnification. So, with the new numbers, it would look like this:

49.5/11= 4.5

However, this isn't the answer. Can anyone help me out with this one?

Thanks in advance!

~Phoenix
 

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What kind of lens is this? And a figure with ray tracing would be best so we can see your work, since I am a little confused by your explanation.
 
I managed to find a diagram that was basically the same idea (ignoring the already drawn ray lines). Essentially, the left side length is 11cm and the right of the lens is 49.5 cm as I found. All my explanation says is I plugged my numbers into the equation for magnification and it didn't work (neither did the negative of that number). I'm using a universally acknowledged equation.

I went up and edited my original post to show that new diagram and (just in case) what the variables mean in the equation.

Can anyone else help me out? Thanks again.
~Phoenix
 
Well the image is inverted so the magnification is negative. Be sure you didn't type something wrong, and also you should type the problem out exactly the way it is worded.
 
I was merely using the wrong distance. Thanks though. :)

Oh, and I just copy and pasted the entire question. That is how it's worded. The image just wouldn't appear.

~Phoenix
 

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