Exam-style question
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What condition is necessary for destructive interference to occur?.
- A.The path difference must be a whole number multiple of the wavelength.
- B.The path difference must be an odd multiple of half the wavelength.
- C.The waves must have the same frequency.
- D.The waves must have different amplitudes.
Model answer
What a good answer should say
- The path difference must be an odd multiple of half the wavelength.
Explanation
Why this works
Destructive interference occurs when the path difference between two waves is an odd multiple of half the wavelength, causing the waves to be out of phase. This results in cancellation of the wave amplitudes, leading to a decrease in overall intensity at the point of interference.
Common mistake
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