Wave Mechanics Question 646
Question: The fundamental frequency of a closed organ pipe of length 20 cm is equal to the second overtone of an organ pipe open at both the ends. The length of organ pipe open at both the ends is
Options:
A) 100 cm
B) 120 cm
C) 140 cm
D) 80 cm
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Fundamental frequency of closed organ pipe $ V _{c}=\frac{V}{4l _{c}} $ Fundamental frequency of open organ pipe $ V _{0}=\frac{V}{2l _{0}} $ Second overtone frequency of open organ pipe $ =\frac{3V}{2l _{0}} $ From question, $ \frac{V}{4l _{c}}=\frac{3V}{2l _{0}} $
$ \Rightarrow l _{0}=6l _{c}=6\times 20=120cm $
BETA
