Question:hard

Fifth overtone of an open pipe of length \(L_0\) is in unison with the fifth overtone of the pipe closed at one end of length \(L_c\).
The ratio \(L_0\) to \(L_c\) is

Show Hint

Find the harmonic numbers for the fifth overtone in each type of pipe.
Updated On: Oct 1, 2026
  • \(11:6\)
  • \(11:12\)
  • \(6:11\)
  • \(12:11\)
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Count overtones:
The first overtone of a closed pipe is the 3rd harmonic. The fifth overtone is the harmonic $2 \times 5 + 1 = 11$. For an open pipe the first overtone is the 2nd harmonic, so the fifth is the 6th.

Step 2: Equate wavelengths:
$\lambda_o = \frac{2L_o}{6} = \frac{L_o}{3}$ and $\lambda_c = \frac{4L_c}{11}$. Equal frequency means equal wavelength, so $\frac{L_o}{3} = \frac{4L_c}{11}$, giving $\frac{L_o}{L_c} = \frac{12}{11}$.

Final Answer:
The ratio is $12:11$, option (D). \[ \boxed{12:11} \]
Was this answer helpful?
0