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Light Problem

  • #1
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Why can't you see light interference in a room, where beams of light come from two different windows?



My Attempt:

Because light has travelled through both more dense mediums of glass, back into the air, where the light 'interferes' the medium of air in a room is so large, and the wavelength is so small, that when they do interfere it is undetectable to the human eye.
 

Answers and Replies

  • #2
Simon Bridge
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You can. The effect is very small because you are not restricting the available paths very much and it tends to wash-out anyway because the light enters the windows any-old how.

To see the effect strongly, your windows need to be close to the size of the wavelength of the light and separated by a similar scale.
Nothing to do with the glass or the air.

Youtube has a lot of Richard Feynman's lectures - he covers the concepts very solidly.
 
  • #3
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Thank you so much man, i appreciate it.
 
  • #4
Simon Bridge
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No worries - Youngs interference is just a special case of a general principle and the way the patterns change smoothly between scales is actually quite beautiful. IMO it's a nice illustration of what physicists mean by things like "simple" and "beautiful". So it's encouraging to see people explore it.
 
  • #5
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I've got another question if you don't mind helping me again. Ive gotta type the solution on my phone or on my pc if I go home so bear with me. Once again with regards to light. Give me a but to type up my answer I'm gonna try to figure how to post the picture of my work if I cam.
 
  • #6
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Question is: why can we hear around corners but not see around corners? (I will post my attempt in the nxt post)
 
  • #7
Simon Bridge
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Because our organs for hearing work differently from our organs of vision.

Sound waves penetrate the sound "shadow" far more than visible light waves penetrate the light shadow because they have much longer wavelengths. Radio waves, which are a kind of light with a very long wavelength, go around corners just fine and we "see" them with radio receivers.
 

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