Reading the derivation for the single slit diffraction minima formula from this site, I'm not convinced about its argument.(adsbygoogle = window.adsbygoogle || []).push({});

http://www.math.ubc.ca/~cass/courses/m309-03a/m309-projects/krzak/index.html" [Broken]

What I'm having trouble understanding is the explanation of the formula for minima when m>1.

For example when dealing with m=2, the explanation is that the slit is split into four sections so there is a phase difference of pi for the paired up point sources and so destructive interference occurs. But if we used 2 sections for m=2 then the paired up point sources have a phase difference of 2pi and constructive interference occurs.

Also when m=3 (or an odd number), it seems we have to revert back to two sections to explain destructive interference which gives a phase difference of 3/2pi which is destructive interference.

Why does using 4 sections for m=2 give the 'right' answer of destructive interference and not 2 sections?

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# Single slit diffraction minima formula misunderstanding

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