Compound Microscope Magnification @ Infinity

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SUMMARY

The discussion centers on the concept of magnification in compound microscopes when the final image is at infinity. It is established that the angular magnification can reach 400X, but the magnification is considered negative, specifically -400X, due to the inverted nature of the image produced. The formula used for calculating magnification is m=(-l0.25/fofe), where the optical tube length is 16cm and the objective focal length is 5mm. The negative sign of magnification is unique to compound microscopes at infinity, contrasting with simple magnifiers and astronomical telescopes, which maintain positive magnification.

PREREQUISITES
  • Understanding of optical principles related to magnification
  • Familiarity with compound microscope components, including objective and eyepiece
  • Knowledge of the formula for calculating magnification in optics
  • Basic grasp of image orientation in optical systems
NEXT STEPS
  • Research the formula for calculating magnification in compound microscopes
  • Study the differences between compound microscopes and simple magnifiers
  • Learn about the optical properties of telescopes, particularly astronomical telescopes
  • Explore the impact of focal lengths on image formation in optical systems
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Optics students, educators in physics, and professionals in microscopy who seek to deepen their understanding of magnification principles in compound microscopes.

RachaelD95
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is magnification negative for a compound microscope at infinity
 
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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.
 

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