1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Light interference homework

  1. Jun 9, 2006 #1
    the question is A plane wave of 400-nm light is incident on a 25-µm slit in a screen, as shown in the figure below. At what incident angle will the first null of the diffraction pattern be on a line perpendicular to the screen?http://img130.imageshack.us/img130/9766/inter9ax.jpg [Broken]

    I really do not where to start. Please help me out, i am so lost.
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Jun 9, 2006 #2

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Well, do you know the condition / formula for single slit interfence?
     
  4. Jun 9, 2006 #3
    it's the one with the sin theta right or something right? please point me to the right track
     
  5. Jun 9, 2006 #4

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I think this can be solved using the Fraunhofer Single Slit Diffraction relationship;

    [tex]a\sin\theta = m\lambda[/tex]

    Where a is the size of the slit, [itex]\lambda[/itex] is the wavelength and m is the order of the minima.
     
  6. Jun 9, 2006 #5
    ok ok i think i am remembering this now, and m would be 1 right for first null. when they say null they mean the minima fully destructive right
     
  7. Jun 9, 2006 #6

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I am assuming that's what null means a minima (I haven't heard that terminology for a while). Yes, the fist minima would be at m = 1. This is different to maximas where the first maxima is at n = 1.
     
  8. Jun 9, 2006 #7
    ok thank you so much now i can find the angle easily
     
  9. Jun 9, 2006 #8

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...
Similar Threads for Light interference homework Date
Double Slit Wave Interference - what is m? Apr 3, 2018
Light wave Interference - Angler Fish Problem Jan 18, 2018
Interference of several waves Jan 11, 2018
Number of fringes in YDSE Dec 20, 2017
Interference in thin films Dec 11, 2017