Waves - Result Question 42

44. The fundamental frequency of a closed organ pipe of length 20cm 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

[2015]

(a) 100cm

(b) 120cm

(c) 140cm

(d) 80cm

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Answer:

Correct Answer: 44. (b)

Solution:

  1. (b) Fundamental frequency of closed organ pipe,

vc=v41c

Fundamental frequency of open organ pipe

v0=v210

Second overtone frequency of open organ pipe =3v2l0

From question, v4lc=3v2l0

10=61c=6×20=120cm



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