English: The fundamental frequency of a sound wave in a tube with either BOTH ends CLOSED can be found using the following equation:

${\displaystyle f_{0}={\frac {v}{2L}}}$

L can be found using the following equation:

${\displaystyle L={\frac {\lambda }{2}}}$

The wavelength, which is the distance in the medium between the beginning and end of a cycle, is found using the following equation:

${\displaystyle \lambda ={\frac {v}{f_{0}}}}$

Where:

f₀ = fundamental frequency

L = length of the tube

v = wave velocity of the sound wave

λ = wavelength