How Does Lens Placement Affect Image Height and Orientation?

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SUMMARY

The discussion focuses on the calculation of image height and orientation when using a diverging lens followed by a converging lens. The diverging lens has a focal length of 0.20 m, and the converging lens has a focal length of 0.17 m. The initial object height is 1.5 cm, and the final image height is determined to be 1.4 cm, inverted, after correcting the calculations for magnification and object distance. Key errors identified include neglecting the change in object size after the first lens and the need to calculate the magnification from both lenses sequentially.

PREREQUISITES
  • Understanding of lens equations, specifically the thin lens formula.
  • Knowledge of magnification calculations in optics.
  • Familiarity with the concepts of object distance and image distance in lens systems.
  • Basic principles of light refraction through diverging and converging lenses.
NEXT STEPS
  • Study the thin lens formula and its applications in optical systems.
  • Learn about the principles of magnification in multi-lens systems.
  • Explore the effects of lens placement on image formation and orientation.
  • Investigate practical applications of diverging and converging lenses in optical devices.
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Students and professionals in optics, physics educators, and anyone involved in the design and analysis of optical systems using lenses.

Rawr
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A 1.5-cm tall object is placed 0.50 m to the left of a diverging lens with a focal length of 0.20 m. A converging lens with a focal length of 0.17 m is located 0.08 m to the right of the diverging lens. What is the height and orientation with respect to the original object of the final image.

Okay, first, I find the distance of the image with respect to the diverging lens first.

-1/.2 = 1/di + 1/.5
di = -0.1428...

Then, I add that distance image to the converging lens distance to get the object distance for the converging lens.

0.08 + -.1428.. = .2228 m

Then I use the lens equation again except with that object distance and the focal length of the converging lens.

1/.17 = 1/di + 1/.2228
di = 1.395...

Then I take the magnification equation and use hi/h0 = -di/d0

hi / (1.5) = -(1.395)/(.5)
Solve for hi.. and get -4.185.

Apparently, that is not the answer. The answer key says that it is 1.4 cm with an inverted image. I don't really know how they get 1.4. Where did I go wrong in my work? Or am I wwwaaayy off with what I'm doing?
 
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For your final di of 1.395 I think you forgot to invert it. It should be 1/1.395.
For the magnification, find the magnification due to the first lens, and then the second lens. The product of the two will give you the final magnification. Your way won't work because after the first lens, the size of the object is not 1.5 cm anymore. Also the object distance changes after the first lens. Work that out and see what you get.
 

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