Which acoustic parameter describes the energy flow of a sound wave through a medium?

Which acoustic parameter describes the energy flow of a sound wave through a medium?

• A. Propagation speed
• B. Wavelength
• C. Period
• D. Intensity

Answer: (D)

Energy flow is described by acoustic intensity. Intensity tells you how much energy from the sound wave passes through a unit area per unit time in the direction the wave is traveling. It depends on the pressure amplitude and the medium’s impedance, with the relationship roughly captured by I ≈ p^2 / Z, where p is the sound pressure and Z is the medium’s impedance. So, stronger pressure fluctuations or a medium that allows easier energy transfer increase intensity. The other options describe different properties: propagation speed is how fast the wave moves through the medium, wavelength is the distance of one cycle, and the period is the time for one cycle. While important, none of these directly quantify the rate at which energy travels through space, which is what intensity measures.

Energy flow is described by acoustic intensity. Intensity tells you how much energy from the sound wave passes through a unit area per unit time in the direction the wave is traveling. It depends on the pressure amplitude and the medium’s impedance, with the relationship roughly captured by I ≈ p^2 / Z, where p is the sound pressure and Z is the medium’s impedance. So, stronger pressure fluctuations or a medium that allows easier energy transfer increase intensity.

The other options describe different properties: propagation speed is how fast the wave moves through the medium, wavelength is the distance of one cycle, and the period is the time for one cycle. While important, none of these directly quantify the rate at which energy travels through space, which is what intensity measures.