Question

The harmonics formed in air column in an organ pipe open at both ends are

• A. Only odd
• B. Only even
• C. Both odd and even
• D. Neither odd nor even

Answer 1

The correct option is C Both odd and even

A harmonic is a note whose frequency is an integral multiple of the particular tube's fundamental frequency.
In case of pipes, open at both the ends, $=2L/n$, where $n=1,2,......$
Frequency $=nV/2L,$ where $n=1,2,......,$ where $V=$ speed of vibration

Notice that a closed tube gives odd-numbered harmonics only, while the open tube will give both odd and even-numbered.