Tuning fork resonance in variable length tube

[robert25pl]

Can somebody help mi out to understand more this problem.
Open at both ends tube with variable length and vibrating tuning fork is helded near one end. Lenght is .5 meter when the sound intensity is maximum.
Find wavelength of sound, tuning fork frequency, and frequency which produce resonance. Thanks for any help

 

[Astronuc]

Think of fundamental frequency and harmonics.

What is the relationship between wavelength with respect to the length of the tube? What is the relationship between speed of sound, wavelength and frequency?

 

[robert25pl]

Since this is open pipe
wavelength = 2L/n frequency f1= nV/2L and 2*f1
is this ok?