Find the greatest length of an organ pipe open at both ends that will have its fundamental frequency in the normal hearing range (20—20,000 Hz). Speed of sound in air = 340 m s-1.
Given:
Speed of sound in air ![]()
We are considering a minimum fundamental frequency of
,
since, for maximum wavelength, the frequency is a minimum.
Length of organ pipe ![]()
We have:

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We know that:![]()


On substituting the respective values in the above equation, we get:


Length of the organ pipe is 8.5 m.