2 light waves
I think it is possible that only 2 light waves get diffracted at the ends of the slit, since diffraction is an interference measure. But i state this based on the scalar diffraction theory, where the Fresnel-Kirchhoff integral operator (or any other approximation that describes...
Think of diffraction as a change in the path of rays. They do not reflect (i.e., they do not obey Snell's law); they simply "diffract", following different paths of propagation. On the other side, each diffraction point gives rise to a secondary wavefront that interfere constructivelly and...