Constructive and Destructive Interference
The principle of super-position can be applied to two or more waves traveling in the same medium at the same time. When the waves meet, the net displacement of the medium is the sum of the individual wave displacements.
Constructive interference occurs where the lines (representing peaks), cross over each other. In other words, when two waves are in phase, they interfere constructively.
Destructive interference occurs where two waves are completely out of phase (a peak lies at the midpoint of two waves. In other words, when two waves are out-phase phase by 180 degrees or π radians, they interfere destructively and cancel each other out.
Click and/or drag to change the location of both sources. Turn them off or on using the check boxes. Adjust the frequencies and phases of the two waves. White regions represent crests and blue regions represent troughs. Can you identify the locations of the constructive and destructive interference?
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