Physics · Sound Waves

JEE Main 2026 — 24 January, Evening Shift — Question 34

The fifth harmonic of a closed organ pipe is found to be in unison with the first harmonic of an open pipe. The ratio of lengths of closed pipe to that of the open pipe is $5 / \mathrm{x}$ . The value of x is $\_\_\_\_$ .

Option A:
4
Option B:
2
Correct
Option C:
1
Option D:
3

Answer: B

Step-by-step solution

$\mathrm{f}_{5 \text { closed }}=\mathrm{f}_{1 \text { open }}$ $\frac{5 \mathrm{v}}{4 \mathrm{~L}_{\text {closed }}}=\frac{\mathrm{v}}{2 \mathrm{~L}_{\text {open }}}$ $\frac{\mathrm{L}_{\text {closed }}}{\mathrm{L}_{\text {open }}}=\frac{5}{2}$ $\mathrm{x}=2$

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 24 January, Evening Shift
Subject: Physics
Chapter: Sound Waves
Topic: Vibrations in rod and Air Columns - Organ pipes