A narrow column air of 20ºC is found to encompass standing waves at frequencies of 390 Hz, 520 Hz and 650Hz and at no frequencies in between these. The behavior of the tube at frequencies less than 390 Hz or more than 650 Hz is not known.
i) Is this an open-open tube or an open-closed tube? Describe.
ii) Determine how long is the tube?
iii) Sketch a displacement graph of 520 Hz standing wave in the tube.
iv) The air in the tube is substituted with carbon dioxide, which consists of a sound speed of 280 m/s. Determine the new frequencies of these three nodes?