Calculating Specimen Size Using Microscope Magnification | Homework Help

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Discussion Overview

The discussion revolves around calculating the real size of a specimen observed under a microscope with a given magnification. Participants explore the relationship between magnification, image size, and real size, while addressing a specific homework problem involving a specimen that occupies a quarter of the field diameter.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • One participant proposes using the formula for magnification, suggesting that the magnification of the image is 40 and the image size is 1600 µm, but expresses confusion about how to apply this to find the real size of the specimen.
  • Another participant advises to ignore the quarter for now and focuses on the relationship between magnification and real size, hinting that the microscope makes objects appear larger.
  • A later reply reiterates the previous point, suggesting that the magnification is equal to the image size divided by the real size of the object, prompting a participant to consider solving for the unknown real size.
  • One participant illustrates the concept by using a simpler example of 2x magnification, explaining that if an object appears 1600 µm, its real size would be 800 µm.
  • Following this, another participant applies the same reasoning to the 40x magnification case, calculating that the real size would be 40 µm based on the earlier discussion.
  • Subsequently, a participant asks how to determine the size of the specimen if it occupies a quarter of the calculated space, leading to a calculation of 10 nm as a potential answer.
  • Another participant encourages critical thinking by presenting a hypothetical scenario involving Titans and a microscope, emphasizing the importance of self-verification of the answer rather than relying on confirmation from others.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and approaches to the problem, with no consensus reached on the final answer or the method of calculation. The discussion remains exploratory, with multiple interpretations of how to apply the magnification concept.

Contextual Notes

Some participants express confusion regarding the application of magnification formulas and the implications of the specimen size relative to the field diameter. There are also unresolved assumptions about the definitions of terms used in the calculations.

lha08
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Homework Statement


If the field diameter on 40X is 1600 µm, and a specimen takes up one quarter of the field, how big is the specimen in real life?

Homework Equations


Magnification of image= Image size/ Real size of object

The Attempt at a Solution


I'm not sure but in the formula, would be put the magnification of the image as 40 and image size as 1600 µm and solve? or would we simply find one quarter of 1600 µm and that would be the actual size of the specimen..? I'm a little confused so could help me clear things up about the differences between the two?
 
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Ignore the quarter for now.

If the magnification is 40x and the image is 1600um then what is the real size of the object (hint the microscope makes things look BIGGER!)
 
mgb_phys said:
Ignore the quarter for now.

If the magnification is 40x and the image is 1600um then what is the real size of the object (hint the microscope makes things look BIGGER!)

Umm...I'm not really sure but all i can think of is that the magnification is 40 which is equal to 1600um divided by the real size of object and do i solve for the unknown?
 
Ignore the algebra an just think what's happening.

If the magnification was 2x then the object would appear twice as big as it really is.
If it appears 1600um then it must really be 1600/2 = 800um
 
mgb_phys said:
Ignore the algebra an just think what's happening.

If the magnification was 2x then the object would appear twice as big as it really is.
If it appears 1600um then it must really be 1600/2 = 800um

So in this case, the magnification is 40x so the object is 40 times bigger than the actual size, so 1600/40= 40 um?
 
lha08 said:
So in this case, the magnification is 40x so the object is 40 times bigger than the actual size, so 1600/40= 40 um?

Good, now if the specimen takes up a quarter of this space, how big is it?
 
Last edited:
BAnders1 said:
Good, now if the specimen takes up a quarter of this space, how big is it?
ahh oki so a quarter of 40 um is equal to 10 nm (that's the answer?)
 
lha08 said:
ahh oki so a quarter of 40 um is equal to 10 nm (that's the answer?)

If you have any doubt as to what the answer is, CONVINCE YOURSELF. What if you were a ridiculously tall Titan of 100ft whose naked eye could only focus on something as close as 4 inches away? Let's say some funny fellow Titan created a device (we'll call it a microscope) which could focus on things up to the unheard of size of ONE CENTIMETER (wow!). Now let's say you were a titan studying the complexities of a human pupil. If your Titan microscope could focus up 10X, and the pupil covered 1/4 of this size, how big would you say a human pupil was, after viewing it through the microscope?

What I'm trying to say is that we aren't allowed to tell you if your answer is correct or not, thus you must think of some extreme situation to test the answer yourself.
 

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