# Diffraction gratings and angular separation

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1. Nov 30, 2014

### Grubstank

Hello everyone,

I came across the following when I was reviewing diffraction gratings:
"The condition for maximum intensity is the same as that for a double slit. However, angular separation of the maxima is generally much greater because the slit spacing is so small for a diffraction grating." (http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/gratcal.html)

I can't think of a reason for why this would be the case, unless I am completely misinterpreting what has been stated. I searched in my textbook for a more satisfying explanation but it does not even mention this particularity about diffraction gratings. Online sources have given short answers similar to hyperphysics' explanation.

Any help is greatly appreciated!

2. Nov 30, 2014

### jerromyjon

I think it is just stating that the maximum intensity of a particular wavelength would be the same angle from the slit in either case but in the diffraction grating the maximum intensity is more spread out (angular separation).