Q 11-14-017NEETJEE MainMedium
Two successive resonant frequencies of a pipe are $450$ Hz and $750$ Hz. The pipe is
Answer: (A) closed at one end, with fundamental $150$ Hz
The difference $300$ Hz would be $f_1$ for an open pipe, but $450$ is not a multiple of $300$. For a closed pipe only odd harmonics exist and successive ones differ by $2f_1$: $f_1 = 150$ Hz, and $450 = 3f_1$, $750 = 5f_1$. ✓
Solution by Sreeraj P, M.Sc Physics