Halliday, Resnick & Walker — Waves–II: Problem 47

A well with vertical sides and water at the bottom resonates at \(7.00 \text{ Hz}\) and at no lower frequency. The air-filled portion of the well acts as a tube with one closed end (at the bottom) and one open end (at the top). The air in the well has a density of \(1.10 \text{ kg/m}^3\) and a bulk modulus of \(1.33 \times 10^5 \text{ Pa}\). How far down in the well is the water surface?