1. Not finding help here? Sign up for a free 30min 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!

Diffraction by single slit - effect of increasing the slit width

  1. Aug 1, 2005 #1
    For diffraction by a single slit, what is the effect of increasing (a) the slit width, and (b) the wavelength? It was a problem on my daughter's final and I never seemed to be able to answer it for her. :confused:
  2. jcsd
  3. Aug 1, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The answer lies in the fact that the minima are located at intervals of [itex]n\lambda / D[/itex] (value of sin)... so a bigger slit (D) makes narower maxima and a larger wavelenght ([itex]\lambda[/itex]) makes wider maxima.
  4. Aug 1, 2005 #3
    for single-slit diffraction, the condition for MINIMUMs is:

    [tex] y \ = \ \frac{m \lambda D}{s} [/tex]

    where y is the distance from central max to the m-th minimum of the diffraction pattern, m a positive integer, λ the wavelength, D the distance between single-slit and distant observation screen where diffraction pattern will be observed, and s the single-slit width. Thus:
    a) increasing single-slit width will decrease width of central max ("shrink the diffraction pattern");
    b) increasing wavelength will increase width of central max ("expand the diffraction pattern")
    Last edited: Aug 1, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Diffraction by single slit - effect of increasing the slit width