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 ms^-1`.

Explanation

Let the length will be I
Here given that
`V=340m/s`
`and n=20 Hz`
`Here lamda/2=I`
`rarr lamda=2I`
we know v=nlamda`
`rarr I=V/(2xxn)=340/(2xx20)`
=34/4=8.5cm`
(for maximum wavelength the fequency is minimum)