Physics

Physics

Problem

Fundamental frequency of an open organ pipe is ff . Match the following two columns for a closed pipe of double the length.
Column IColumn II
(a) Fundamental frequency(p) 1.25f1.25 f
(b) Second overtone frequency(q) ff
(c) Third harmonic frequency(r) 0.75f0.75 f
(d) First overtone frequency(s) None of these
Intuitive explanation

The key is understanding how pipe geometry changes the harmonic series. An open pipe supports all harmonics (1, 2, 3, 4, ...), while a closed pipe supports only odd harmonics (1, 3, 5, 7, ...). When you double the length, the fundamental frequency halves—but then you must identify which harmonic number each term refers to, since "overtone" and "harmonic" count differently in closed pipes.

Intuitive explanation

The key is understanding how pipe geometry changes the harmonic series. An open pipe supports all harmonics (1, 2, 3, 4, ...), while a closed pipe supports only odd harmonics (1, 3, 5, 7, ...). When you double the length, the fundamental frequency halves—but then you must identify which harmonic number each term refers to, since "overtone" and "harmonic" count differently in closed pipes.

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