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Homework Help: Light inteference question

  1. Jan 29, 2006 #1

    MathematicalPhysicist

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    Gold Member

    i need to prove that sin(b_n)=(n*lambda)/d
    while dX=(lambda*L)/d

    this is a situation of monochromatic light inteference where dX is the is the distance between every adjacent light spots, lambda is ofcourse the light wavelength, L is the width between the two screens, d is the distance between the gaps of first screen and n describes the place of light spots.

    i know it's rather simple but my text doesnt reveal all the simple algebraic and trigonometric tricks.
    but i think that if we were to build a right triangle then n*dX equals one of its sides while L is the other and by pythogrean sentence the hypotenuse equals:
    D=sqrt(L^2+n^2*(dX)^2)
    and then sin(b_n)=(n*dX)/D
    but this is as far as i went and i didn't get the formula i needed to prove, your input is appreciated.
     
  2. jcsd
  3. Jan 29, 2006 #2

    Astronuc

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    Staff Emeritus
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