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Question
Explain constructive and destructive interference with the help of a diagram?
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Solution
Constructive and destructive interference:
- Points, where the crest of one wave coincides with the crest of another wave and where the trough of one wave coincides with the trough of another wave, are points with the maximum displacement. At these points, displacement is twice that for each wave. These are points of constructive interference.
- Points, where the crest of one wave is coincident with the trough of another, are points with zero displacements. These are points of destructive interference.

Interference for waves
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`[sin 45^circ = cos 45^circ = 1/sqrt 2]`




