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Double-slit experiment - introduction


Light from two coherent sources, S1 and S2, constructively interfere at a point P.
Shown below are the displacements of the light waves:
(i) at S1 -
(ii) at S2 -
Which of the following is true for constructive interference at P?
Note: n is an integer. Take x to be positive for points above O. You may also use
Choose 1 answer: