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A closed organ pipe has a length of 85 cm . If the speed of sound in air is 340 m s ⁻¹ , the frequency of its first overtone is ________ Hz .

Correct answer

300

Step-by-step solution

For a pipe closed at one end, the allowed frequencies are odd harmonics of the fundamental frequency. The fundamental frequency is given by f₁ = v 4L . The first overtone corresponds to the third harmonic, so its frequency is f₃ = 3f₁ = 3v 4L . Given: Length of the pipe, L = 85 cm = 0.85 m Speed of sound, v = 340 m s ⁻¹ Substituting the values: f₃ = 3 340 4 0.85 = 1020 3.4 = 300 Hz Answer: 300

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