Question bank/NEET UG/Physics

NEET UGPhysicsModerateRe-NEET 2026

For sound waves, if the number of nodes for the 5th harmonic of an open-ended pipe is nn and that for the 9th harmonic of the same pipe with one of its ends closed is mm, the ratio nm\frac{n}{m} is

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Sol. For open organ pipe
→\rightarrow Number of nodes are same as number of harmonics
∴n=5\therefore n=5
For closed organ pipe
→\rightarrow There are only odd harmonics
For 1st1^{\text{st}} harmonic →\rightarrow Number of node →1\rightarrow 1
For 3rd3^{\text{rd}} harmonic →\rightarrow Number of node →2\rightarrow 2
For 5th5^{\text{th}} harmonic →\rightarrow Number of node →3\rightarrow 3
For 7th7^{\text{th}} harmonic →\rightarrow Number of node →4\rightarrow 4
For 9th9^{\text{th}} harmonic →\rightarrow Number of node →5\rightarrow 5
∴m=5\therefore m = 5
→nm=55=1\rightarrow \frac{n}{m} = \frac{5}{5} = 1

Source: geekyrakshit/indian-exam-questions / reneet2026-code50

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