Understanding Double Slit Interference: How Do We Count Fringes?

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SUMMARY

The discussion focuses on the counting of fringes in double slit interference patterns, specifically addressing the values of m for bright and dark fringes. The central bright fringe corresponds to m=0, while the first bright fringe is m=1. Dark fringes occur at m=1.5, m=3.5, etc., where the path length difference is half a wavelength. Understanding these fringe values is crucial for accurately interpreting interference patterns in physics.

PREREQUISITES
  • Basic understanding of wave interference principles
  • Familiarity with the double slit experiment
  • Knowledge of wavelength and path length concepts
  • Ability to interpret fringe patterns in physics
NEXT STEPS
  • Study the mathematical derivation of fringe positions in double slit interference
  • Learn about the relationship between wavelength and fringe spacing
  • Explore the concept of path length difference in wave interference
  • Investigate applications of double slit interference in modern physics experiments
USEFUL FOR

Students studying physics, educators teaching wave mechanics, and anyone interested in the principles of light interference and its applications.

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Homework Statement


When they say the first and third bright fringe, do they mean m=1 and m=0..do we count m=0?
And likewise for when they say first and third dark fringe, is it m=1.5 and m=3.5?
How would we know when to count m=0?
Thanks


Homework Equations





The Attempt at a Solution

 
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The central bright fringe is the place when the path length form the two slits is zero.
The dark fringes on each side of this central fringe is where the path lengths differ by half a wavelength.
The bright fringes outside of those is where the path lengths differ by one full wavelength.
And so on...
That's the physics of the thing.
Now what's this character m? Never heard of him.
Suggest you write out some equation where it appears and explain what it stands for.
 

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