Two coherent sources of light produce interference (destructive) when the phase difference between them is _________?
Correct answer: A. π
- A. π
- B. 2π
- C. π/2
- D. π/4
Explanation
Destructive interference occurs when the waves arrive out of phase by an odd multiple of π radians, such as π radians, so their displacements cancel. A phase difference of 2π radians produces constructive interference instead. The likely mistake is choosing π/2, which gives neither complete constructive nor complete destructive interference.
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About Superposition and Interference
Superposition states that overlapping waves produce a resultant displacement equal to the algebraic sum of their individual displacements. Interference covers constructive and destructive interference, phase difference, path difference, coherent sources, and conditions for maxima and minima. It differs from diffraction, which involves spreading around openings or obstacles.
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