Question

Some pipe organs create sounds lower than humans can hear. This ""infrasound"" can still create physical sensations. What is the fundamental frequency of the sound from an open-open pipe that is 32 feet long (a common size for large organs)? What length open-closed tube is necessary to produce this note? Assume a sound speed of 343 m/s.

Answer 1

Answer: 17.59 Hz and 4.87 m

Explanation:

The fundamental frequency of the sound from an open-open pipe is given as

f= $\frac{v}{2L}$

where v= 343 m/s

L= 32 feet= $\frac{32}{3.281}$ = 9.75 m

So,

f= $\frac{343}{2*9.75}$ = 17.59 Hz

The length of open-closed tube is related to frequency by formula

f= $\frac{v}{4L}$

or L=$\frac{v}{4f}$

L= $\frac{343}{4*17.59}$

L= 4.87 m