Why does 2slit interference depend on wavelength?

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Discussion Overview

The discussion centers on the dependence of double-slit interference patterns on the wavelength of light. Participants explore the conceptual understanding of how waves interact in this context, touching on foundational aspects of wave theory and the nature of interference.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how two waves in a double slit interact and why interference patterns depend on wavelength, expressing confusion about the relationship between wavelength and the orientation of the slit.
  • Another participant explains that interference occurs because waves of the same wavelength can add or cancel based on their paths, suggesting that wavelength and spatial layout are interconnected in producing interference patterns.
  • Some participants indicate that a foundational understanding of wave properties is necessary to grasp the concept of interference, implying that the original question may stem from a lack of familiarity with basic wave theory.
  • There are references to diagrams and visual aids as helpful tools for understanding the principles of wave interference.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding wave theory and its application to double-slit interference. There is no consensus on the conceptual clarity of the relationship between wavelength and interference patterns, indicating ongoing uncertainty and differing perspectives.

Contextual Notes

Some participants suggest that a deeper understanding of wave definitions, such as wavelength and displacement, is essential for making progress in this discussion. There is an acknowledgment that translating theoretical concepts into intuitive understanding can be challenging.

toesockshoe
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How do 2 waves in a double slit get cut? I know that light spreads in all directions so, when a double slit is infront of a light source, then it only allows light that goes through the slit past the wall. Why do interference patterns depend on the wavelength? Isnt the wave length perpendicular to the orientation of the slit? I would image the interference patters depend on the angle with which the light gets cut, but I don't see conceptually how it depends on the wavelengths. Can someone explain this conceptually?
 
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The reason the interference works is that waves of the same wavelength, taking different paths, can add and cancel, depending on where they arrive. Wavelength and the spatial layout of the situation go together to produce an interference pattern.

Interference happens because of the basic properties of waves. The way you are using terms in your question makes me think that you need to start at the very beginning of Wave Theory. I can't tell what stage you are at in your Physics but this link could (don't be offended) be a suitable start. Fire up Google and find a few links about waves and you can then graduate to interference. Hyperphysics (easy to find) is always a good source of concise Physics information but it often requires some extra reading around.
 
I can explain it diagramatically:
upload_2016-1-30_17-14-56.png

Image adapted by Dr Greg from File:Two-Slit Experiment Light.svg, public domain.
upload_2016-1-30_17-14-56.png
 
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DrGreg said:
I can explain it diagramatically:
I have a feeling that the real problem here is understanding the basic way waves work. (i.e. a couple of stages earlier)
Like here:
toesockshoe said:
Isnt the wave length perpendicular to the orientation of the slit?
Translating graphs and diagrams into a feel for what they actually represent can be a problem. That's why I recommended reading around the basics of waves first. Definitions of wavelength, displacement, wave speed etc. are essential for making progress with something as abstract as waves.
 

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