Question

In open organ pipe, if fundamental frequency is n, then the other frequencies are:

• A. n, 2 n, 3n, 4n
• B. n, 3n, 5n
• C. n, 2n, 4n, 8n
• D. none of these

Answer 1

Answer: (A)

In an open organ pipe, both ends of the pipe are open. There are pressure nodes (or displacement antinodes) at both ends. In open pipe at both ends, the natural frequencies of oscillation form a harmonic series that includes all integral multiples of the fundamental frequency, i.e, all even and odd harmonics are present. Therefore, if fundamental frequency is $n$, then other frequencies are $n,2n,3n,4n,\dots .$