The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz. What is the fundamental frequency of the system ?

1. 20 Hz

2. 30 Hz

3. 40 Hz

4. 10 Hz

Doubtly Asked 30 Oct 2026 NEET UG 2017 Practice test neet Save WhatsApp Report

1 answer

Best answer

Answer: 1. 20 Hz

Key idea: a tube closed at one end has only odd harmonics: \(f_0,3f_0,5f_0,\dots\). Consecutive harmonics differ by \(2f_0\).

\(260-220=40=2f_0\Rightarrow f_0=20\) Hz.

Check: \(220=11f_0\) and \(260=13f_0\), both odd.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

Was this answer helpful?