Introductionreflection, return of a wave from a surface that it strikes into the medium through which it has traveled. The general principles governing the reflection of light and sound are similar, for both normally travel in straight lines and both are wave phenomena. Objects are visible because of the light reflected from their surfaces, and their color depends on their ability to reflect light of a certain wavelength and to absorb that of other wavelengths. The reflection of sound waves from a surface is called an echo.
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