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Question 31218
JEE Physics · Hard

Sound Waves: Speed of Sound MCQ

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Speed of SoundHardQuestion 31218

Question

Speed of sound is higher in moist air than dry air because:
  1. A
    Water vapour is heavier
  2. B
    Humidity increases γ
  3. C
    Effective molar mass decreases (water replaces heavier nitrogen)
    Correct
  4. D
    Temperature increases in humid air

Correct answer

Effective molar mass decreases (water replaces heavier nitrogen)

Explanation

Molar mass of water vapour (18 g/mol) < nitrogen (28 g/mol). Humid air has lower average M → higher v = √(γRT/M).

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