How to Determine Minimum Thickness for Dark and Bright Spots in Soap Films?

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SUMMARY

The discussion focuses on calculating the minimum thickness of a soap film that produces dark and bright spots when illuminated by light of wavelength 580 nm. For dark spots, the formula used is 2t = m (wavelength), while for bright spots, the formula is 2t = (m + 1/2) (wavelength). Given the refractive index of the soap film (n=1.33), users can directly substitute the values into these equations to find the required thicknesses for both types of interference patterns.

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  • Knowledge of basic algebra for solving equations
  • Experience with light wavelength measurements
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Homework Statement


Light of wavelength 580 nm strikes a soap film (n=1.33), which is surrounded by air. What is the minimum thickness needed to produce
a) dark spot?
b) bright spot?


Homework Equations


n1/n2=wavelength 2 / wavelength 1

2t = m (wavelength) <-- dark
2t = (m + 1/2) (wavelength) <--- bright
 
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Those equations are right. Just plug in the numbers are you're done.
 

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