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Question 31388
JEE Physics · Hard

Waves on String: Mode Mixing MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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Mode MixingHardQuestion 31388

Question

A string is plucked at x = L/4 from one end. Which harmonics are absent in the sound produced?
  1. A
    Even harmonics
  2. B
    Odd harmonics
  3. C
    Multiples of 4 (4th, 8th, 12th...)
    Correct
  4. D
    No harmonics are absent

Correct answer

Multiples of 4 (4th, 8th, 12th...)

Explanation

Plucking at x = L/4 excites all modes except those with a node at L/4. Modes with node at L/4: n = 4, 8, 12,... (where nπ×(L/4)/L = nπ/4 = mπ → n = 4m). Harmonics 4, 8, 12,... are suppressed.

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