Physics

Physics

Problem

A pipe X has both ends open and a pipe Y has one open and one closed end. The second harmonic in X has the same frequency as the first harmonic in Y. Calculate the ratio of the length of pipe X to that of pipe Y.
Intuitive explanation

The key is recognizing that open and closed pipes have different harmonic patterns: open pipes resonate at all integer multiples of the fundamental, while closed pipes only at odd multiples. Since the second harmonic of X matches the first harmonic of Y, you need to set their frequencies equal using f=nv2Lf = \frac{nv}{2L} for open pipes and f=nv4Lf = \frac{nv}{4L} for closed pipes, then solve for the length ratio.

Intuitive explanation

The key is recognizing that open and closed pipes have different harmonic patterns: open pipes resonate at all integer multiples of the fundamental, while closed pipes only at odd multiples. Since the second harmonic of X matches the first harmonic of Y, you need to set their frequencies equal using f=nv2Lf = \frac{nv}{2L} for open pipes and f=nv4Lf = \frac{nv}{4L} for closed pipes, then solve for the length ratio.

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