Slit diffraction occurs due to Huygens' principle, where each point in a wave acts as a source for new waves, leading to scattering independent of the material properties of the slit. It differs from Bragg diffraction, which involves scattering by the atomic structure of a solid. The discussion highlights that slit diffraction is a fundamental wave phenomenon rather than a material-specific interaction. Additionally, when two electromagnetic waves interfere, their amplitude change is not permanent; they return to their original states once separated. Understanding these principles clarifies the nature of wave interactions and diffraction phenomena.
