Question

The two nearest harmonics of a tube closed at one end and open at other end are 220hz and 260hz.What is the fundamental frequency of the system

Answer 1

For a tube closed at one end and open at other end, fundamental mode is v/(4L) Hz, where v is velocity of sound and L is length of tube.  Two nearest modes differ by 2v/(4L) Hz

 

2v/(4L) = 260-220 = 40 Hz

Hence, fundamental mode v/(4L) = 20 Hz