The Wave Nature of light: Interference Chapter 30 30-1 Huygens Principle and Diffraction p680-681 1. Diffraction光的衍射现象(p681) If a wave encounters(遇到) a barrier(障碍物) that has an opening(fl) of dimensions similar to the wavelength, the part of the wave that passes through the opening will spread out (diffract) into the region beyond the barrier.The Wave Nature of Light; Interference Chapter 30 30-1 Huygens’ Principle and Diffraction p680-681 1.Diffraction 光的衍射现象 (p681) If a wave encounters（遇到） a barrier（障碍物） that has an opening（孔） of dimensions similar to the wavelength, the part of the wave that passes through the opening will spread out (diffract) into the region beyond the barrier