Help with Newton's Rings Homework Questions

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SUMMARY

The discussion focuses on solving homework questions related to Newton's Rings, specifically involving a planoconvex glass lens with a refractive index of 1.54 and a diameter of 14.3 cm. The experiment utilizes 585 nm light, resulting in the observation of 8 bright rings. Key formulas discussed include t = m(λ)/2n for thickness and R = r²/(mλn) for radius of curvature. The user expresses difficulty in applying these formulas correctly to derive the thickness, radius of curvature, and focal length of the lens.

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  • Understanding of Newton's Rings experiment
  • Familiarity with optical physics concepts
  • Knowledge of the refractive index and its implications
  • Proficiency in applying formulas related to wave interference
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  • Study the derivation of the Newton's Rings formula
  • Learn about the relationship between refractive index and optical path length
  • Explore the concept of focal length in lens systems
  • Practice solving problems involving wave interference and lens optics
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Students studying optics, physics educators, and anyone seeking to understand the principles of Newton's Rings and their applications in optical experiments.

Knicks685
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Hi. I have some homework questions here that I need a little help on. I know the fomulae to use just do not know how to apply it properly. Any help will be appreciated.

In a Newton's Ring experiment, a planoconvex glass (n=1.54) lens having a diameter 14.3 cm is placed on a flat plate. When 585 nm light is incident normally, 8 bright rings are observed with the last one right on the edge of the lens, at r.

1. What is the thickness of the lens?
2. What is the radius of curvature of the convex surface of the lens?
3. What is the focal length of the lens?
 
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not that i can answer this but if you read the FAQ you are supposed to show some working or some effort to have started your problem, maybe if you do that you will have more of a chance of it being answered
 
Well I know that at the center there is a dark spot so to find the thickness of the lens I'd assume that t=m(lambda)/2n but I get an unreasonable answer. To find the radius of curvature I tried using r=sqroot(m(lambda)R/n therefore R=r^2/(m*lambda*n) but again I don't think I'm getting the right answer. I'm not trying to catch a break here. So any help will be appreciated.
 

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