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Question about light and interference

  1. Oct 21, 2006 #1
    Hello to all,

    I searched the different forums for an explanation but have not found one complete enough yet… the question is about light interference and goes like this ;

    Can you explain or point me towards a link that explains why the light in everyday life doesn’t interfere with itself ?

    I mean, when I look around me, the ‘continuum’ of space that my eyes scan, is full of an incredibly high number of light beams reflected from an equally high number of surfaces, coming from all directions.

    How come, given all this wave carried information, is there no interference taking place ?

    What is the property or properties of light that makes it all appear just right ?


  2. jcsd
  3. Oct 21, 2006 #2


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    Firstly some interfence will be occuring, however, often it will not be noticable since (a) the sources will not be coherent (b) there will be a large range of wavelengths.
  4. Oct 21, 2006 #3


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    Light in everyday life often does interfere with itself. Every time you see colors in a soap bubble or an oil slick on a puddle you are seeing the effects of interference. The lenses in eyeglasses are often coated with thin films to make the surfaces less reflective, an effect that is achieved because of interference. The reason light interference is not more prevalent is that the wavelength is so short compared to the typical spacing between objects and the surface roughness of most objects. To see interference effects you need to have very smooth surfaces and at most very gradual changes in thickness or separation.

    Longer length waves like sound or water waves can be heard or seen to interfere very readily. The vibrations of strings on stringed instruments exhibit wave interference every time they make a sound.
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