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: Wave nature of light problem

  1. May 3, 2005 #1
    Given a wavelength length [tex]\alpha[/tex], what is the maximum Width (D) of a single slit, which would have no diffraction minima?

    It seems like a proof problem to me and I am trying to get a head start.
    should I use [tex] D * sin (\theta) = m \alpha[/tex] ?
     
  2. jcsd
  3. May 3, 2005 #2

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    Yes, that and what you know about the sine function.
     
  4. May 3, 2005 #3
    that sin of zero degrees is 0
     
  5. May 4, 2005 #4

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    Yes, but at zero degrees you will never have a minimum. From the geometry of the single slit diffraction setup, to not find any minima after the slit, the angle [itex] \theta [/itex] would have to be 90 degrees for the first minimum. So then what does

    [tex] D * sin (\theta) = m \alpha[/tex]

    tell you about D?
     
  6. May 4, 2005 #5
    I see, so [tex]D sin (90) = (1) \alpha[/tex], which is the first minimum, and D has to be equal to the wavelength [tex]\alpha[/tex].
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook