Compound Microscope Magnification @ Infinity

Click For Summary

Discussion Overview

The discussion revolves around the magnification of a compound microscope when the final image is at infinity. Participants explore the implications of negative magnification in this context, comparing it to other optical devices like simple magnifiers and astronomical telescopes.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants suggest that the negative sign of magnification for a compound microscope at infinity indicates an inverted image.
  • One participant references a specific formula for magnification and questions why the magnification is taken as -400x in their calculations.
  • Another participant argues that the sign of magnification remains consistent regardless of the position of the final image, stating that using infinity simplifies calculations.
  • There is a contention regarding the nature of magnification in different optical devices, with some asserting that simple magnifiers maintain positive magnification while compound microscopes do not.
  • One participant challenges the notion that focusing at infinity is unique to compound microscopes, noting that astronomical telescopes can also focus at distances closer than infinity without changing the orientation of the image.

Areas of Agreement / Disagreement

Participants express differing views on the nature of magnification in compound microscopes versus other optical devices. The discussion remains unresolved, with no consensus on the reasons behind the negative magnification or its implications.

Contextual Notes

Participants reference specific formulas and examples, but there are indications of missing assumptions and varying interpretations of optical principles. The discussion does not clarify the conditions under which the magnification sign is determined.

RachaelD95
Messages
3
Reaction score
0
is magnification negative for a compound microscope at infinity
 
Science news on Phys.org
welcome to PF
Is this what you wanted? An inverted image implies a negative sign for the magnification.
 
I done a question where the formula was m=(-l0.25/fofe) as the final image was at infinty.
  1. The angular magnification of a microscope is 400X when the final image is at infinity. The optical tube length is 16cm and the focal length of the objective is 5mm. What is the focal length of the eyepiece?

    They took the magnification to be -400x not sure why? The only thing I could take from it was that when its a compound microscope at infinity the magnification is negative.
 
RachaelD95 said:
I done a question where the formula was m=(-l0.25/fofe) as the final image was at infinty.
  1. The angular magnification of a microscope is 400X when the final image is at infinity. The optical tube length is 16cm and the focal length of the objective is 5mm. What is the focal length of the eyepiece?

    They took the magnification to be -400x not sure why? The only thing I could take from it was that when its a compound microscope at infinity the magnification is negative.
Wherever you choose to put the final (virtual) image, the magnification will still have the same sign. Using infinity just makes the calculation easier.
 
So why is the magnification negative? It only seems to be for a compound microscope at infinity the magnification is negative. For a simple magnifier and astrological magnification remains positive
 
RachaelD95 said:
So why is the magnification negative? It only seems to be for a compound microscope at infinity the magnification is negative. For a simple magnifier and astrological magnification remains positive
I don't know where you got that from. Both the astronomical telescope (not the galilean telescope) and the microscope produce inverted real images - which is what the sign tells you. Also, I don't understand where you got the bit about 'focussed at infinity' as being special. You can easily focus a telescope at closer than infinity; for people with short sight and no glasses, for instance. The image is still the same way up! (i.e. inverted)
Are you using more than one source for you information? You may find that the sign has been omitted in one source.
 

Similar threads

Undergrad Higher magnification calibration slide
  • · Replies 5 ·
Replies
5
Views
535
Undergrad Compound Microscope System: Magnification Power Explained
  • · Replies 5 ·
Replies
5
Views
3K
High School Magnification of an Astronomical Telescope
  • · Replies 2 ·
Replies
2
Views
9K
High School Huh? Seeing crisp vitreous floaters while using microscope
  • · Replies 7 ·
Replies
7
Views
3K
High School What is the standard distance for viewing with a microscope?
  • · Replies 5 ·
Replies
5
Views
8K
Undergrad Explanation for homemade digital microscope's optical systems?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Color and appearance of a "pile" of biological viruses
  • · Replies 10 ·
Replies
10
Views
2K
Focal length of the eyepiece lens in a compound microscope
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad How Do Electromagnetic Lenses Magnify the Image?
  • · Replies 10 ·
Replies
10
Views
2K
High School What is the Length of a Compound Microscope?
  • · Replies 4 ·
Replies
4
Views
3K