Question:

A pipe closed at one end vibrating in fifth overtone is in unison with open pipe vibrating in its fifth overtone. The ratio of \(l_c : l_o\) is [\(l_c = \text{vibrating length of closed pipe}, l_o = \text{vibrating length of open pipe}\)]

Show Hint

Closed pipe: Only odd harmonics
Updated On: May 8, 2026
  • 12 : 11
  • 1 : 1
  • 11 : 12
  • 5 : 1
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation


Concept:
• Closed pipe frequencies: odd harmonics
• Open pipe frequencies: all harmonics

Step 1:
Fifth overtone.
• Closed pipe: 6th harmonic not allowed → 11th harmonic \[ f_c = \frac{11v}{4l_c} \]
• Open pipe: 6th harmonic \[ f_o = \frac{6v}{2l_o} = \frac{3v}{l_o} \]

Step 2:
Equate frequencies. \[ \frac{11v}{4l_c} = \frac{3v}{l_o} \]

Step 3:
Solve. \[ \frac{l_c}{l_o} = \frac{11}{12} \]

Step 4:
Conclusion.
Ratio = $11:12$ Final Answer: Option (C)
Was this answer helpful?
0
0