In an open-open tube, what is the fundamental wavelength in terms of the length L?

In an open-open tube, what is the fundamental wavelength in terms of the length L?

• A. L/2
• B. 2L
• C. L
• D. 4L

Answer: (B)

In an open-open tube, the ends are free to move air, creating pressure nodes and displacement antinodes at both ends. The fundamental standing wave fits exactly one half-wavelength into the length of the tube, so the length L equals λ/2. Solving gives the fundamental wavelength λ = 2L. The other options don’t satisfy this half-wavelength fit for the fundamental (they would correspond to higher harmonics or don’t align with the open-end boundary conditions).

In an open-open tube, the ends are free to move air, creating pressure nodes and displacement antinodes at both ends. The fundamental standing wave fits exactly one half-wavelength into the length of the tube, so the length L equals λ/2. Solving gives the fundamental wavelength λ = 2L. The other options don’t satisfy this half-wavelength fit for the fundamental (they would correspond to higher harmonics or don’t align with the open-end boundary conditions).