6B-4 Superposition of Waves
The principle of superposition states that when two or more waves traverse the same space, a disturbance occurs that is the sum of the disturbances caused by the individual waves. This principle applies to electromagnetic waves, whereby the disturbances involve an electrical field, as well as to several other types of waves, whereby atoms or molecules are displaced. When electromagnetic waves differing in frequency, amplitude, and phase angle pass some point in space simultaneously, the principle of superposition and Equation 6-5 permits US to write