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QJEEM23Phd66a: JEE Main 2023 Physics - Class 11 JEEM23Phd66a Solution: An organ pipe 40   cm long is open at both ends. The speed …

An organ pipe 40 cm long is open at both ends. The speed of sound in air is 360 ms−1. The frequency of the second harmonic is ___________ Hz.

Step-by-Step Verified Solution

An organ pipe that is open at both ends resonates at all harmonics, including the fundamental (first harmonic), second harmonic, third harmonic, etc.

The frequency ff of the nn -th harmonic for a pipe open at both ends is given by:

fn=nv2Lf_n = \frac{n v}{2L} ,

where:

  • nn is the number of the harmonic,
  • vv is the speed of sound, and
  • LL is the length of the pipe.

To find the frequency of the second harmonic ( n=2n = 2 ), we can substitute the given values into the formula:

f2=2×3602×0.4=900 Hzf_2 = \frac{2 \times 360}{2 \times 0.4} = 900 \, \text{Hz} .

Therefore, the frequency of the second harmonic is 900 Hz900 \, \text{Hz} .

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