Which term describes the rate at which energy is transferred by a sound wave?

Which term describes the rate at which energy is transferred by a sound wave?

• A. Power
• B. Intensity
• C. Frequency
• D. Amplitude

Answer: (A)

Power is the rate at which energy is transferred. A sound wave carries energy as it moves, and the amount of energy crossing a point per second is the power of the wave. If you instead look at energy per unit area, that’s called intensity—the power per area—so intensity depends on both the energy and how large the area is. Frequency is about how often the pressure oscillates (pitch), and amplitude relates to the strength of the oscillations (how loud the wave can be), but neither alone describes the rate of energy transfer.

Power is the rate at which energy is transferred. A sound wave carries energy as it moves, and the amount of energy crossing a point per second is the power of the wave. If you instead look at energy per unit area, that’s called intensity—the power per area—so intensity depends on both the energy and how large the area is. Frequency is about how often the pressure oscillates (pitch), and amplitude relates to the strength of the oscillations (how loud the wave can be), but neither alone describes the rate of energy transfer.