Q. For sound waves, if the number of nodes for the 5ᵗʰ harmonic of an open-ended pipe is n and that for the 9ᵗʰ harmonic of the same pipe with one of its ends closed is m, the ratio n/m is
A) 3/5
B) 5/9
C) 9/5
D) 1
Explanation
[Solution from source] In an open pipe the pᵗʰ harmonic has p displacement nodes, so n = 5. In a closed pipe the (2k − 1)ᵗʰ harmonic has k nodes (including the closed end); the 9ᵗʰ harmonic has k = 5, so m = 5. Hence n/m = 1. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.