What are coherent sources ? Please explain.

What are coherent sources ? Please explain.

Grade:12th pass

1 Answers

Apoorva Arora IIT Roorkee
askIITians Faculty 181 Points
8 years ago
  1. For observing interference phenomenon coherence of light waves is a must.
  2. For light waves emitted by two sources of light , to remain coherent the initial phase difference between waves should remain constant in time. If the phase difference changes continously or randomly with time then the sources are incoherent.
  3. Two independent sources of light are not coherent and hence can not produce interference because light beam is emitted by millions of atoms radiating independently so the phase difference between waves from such sources fluctuates randomly many times per second.
  4. The coherent sources can be obtained either by the source and obtaining its virtual image or by obtaining two virtual images of the same source. This is because any change of phase in real source will cause a simultaneous and equal change in its image.

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