If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Double-slit experiment - introduction

Problem

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: