# Energy Dispersion in Young's Double Slit Experiment

In Young's double slit experiment, when you see the diffraction pattern, why does the intensity of the light fade out as you move from the central maximum? I think it has something to do with the wave-particle duality but I'm not sure and my teacher has no idea. See images below to see what I'm talking about. Where does that energy go? I'm not talking about the actual interference pattern, but the intensity of the light.

(source: cyberphysics.co.uk)

• There is no intensity missing. All energy passing through the slit lands on the screen. – my2cts Aug 4 '19 at 9:06

The answer I gave before was wrong, as was kindly pointed out by CuriousOne. The fading of the intensity isn't because of the $1/r^2$ fall-off of light, since the diffraction formulas are only for small angles anyway.