Translations:Analogy/48/en
Two or more superimposed waves clearly produce a wave that is different from either wave alone. The superposition of waves and the resulting interference phenomena are fundamental to the study of diffraction. Longitudinal sound waves can interfere to produce beats. In a similar way, the interference of transverse light waves produces colors. Constructive and destructive interference are sketched in Figure 23. The interference of water waves is a common sight. In some places, crests overlap crests, and in other places, crests overlap troughs. There is no clear physical distinction between the phenomena of interference and diffraction. It has become customary, however, to speak of interference when referring to the superposition of a few waves and to speak of diffraction when a great many or an infinite number of waves are superposed. >
