How diffraction of a wave through a aperture in terms of the uncertain

1. Aug 12, 2010

Flupdoodle

How could you describe qualitatively how diffraction of a wave through a aperture in terms of the uncertainty principle?

Cat

2. Aug 13, 2010

cragar

Re: Diffraction

lets take a single slit and shine light through it . If i make this slit smaller and force the light to go through it , i know to much about the position of the photons they must be though that opening (delta x) so now i must get an uncertainty in the momentum of the photons , so (dx)(dp)=(h-bar) , When i make the slit to small the light starts to spread out and diffract .
The smaller i make the slit the more uncertainty i will have in the photons momentum .
I don't know if this is what you were looking for .

3. Aug 16, 2010

Flupdoodle

Re: Diffraction

Thank you, much appreciated.

4. Aug 16, 2010

sophiecentaur

Re: Diffraction

Does that treatment yield a sin(x)/x distribution? Wave theory does- and it agrees with measurement very well.

5. Aug 17, 2010

cragar

Re: Diffraction

These might not answer your question but you might want to look at them.
http://univirtual.info/elementaryphysics/pc/cutnell3158c29/cutnell3158c29_7.htm [Broken]
https://www.physicsforums.com/showthread.php?t=227296

Last edited by a moderator: May 4, 2017
6. Aug 17, 2010

sophiecentaur

Re: Diffraction

Oh I see, now. Interesting. The calculations do, in fact, seem to use a wave approach to get actual values but relate it to uncertainty. Fair enough - it's always useful to tie things together.

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