Which term denotes the energy loss per unit distance traveled by a sound wave?

• A. Attenuation coefficient
• B. Attenuation
• C. Amplitude
• D. Bandwidth

Answer: (A)

Energy loss per unit distance traveled by a sound wave is quantified by the attenuation coefficient. Attenuation describes the overall weakening of the signal as it propagates, due to absorption, scattering, and reflection. The attenuation coefficient is the rate at which that loss occurs per centimeter, usually expressed in dB/cm. The total attenuation over a distance equals the attenuation coefficient multiplied by the distance. This is why higher frequencies attenuate more, since the coefficient rises with frequency. Amplitude refers to the wave’s strength at a point and isn’t a per-distance rate, while bandwidth is about the range of frequencies present.