Attenuation is the loss of ultrasonic wave energy during propagation due to which factors?

• A. Reflection and refraction
• B. Dispersion and diffraction
• C. Absorption and scattering
• D. Composition and shape

Answer: (C)

Attenuation is the reduction of ultrasonic energy as the wave travels through a material. The primary causes are absorption and scattering. Absorption converts part of the acoustic energy into heat within the material, while scattering redirects energy away from the main beam, either out of the path or in directions that don’t contribute to the useful signal. Together, these mechanisms decrease the wave’s amplitude with distance, defining how much signal is lost during propagation.

Reflection and refraction describe energy changes at interfaces, not the gradual loss during transit. Dispersion and diffraction relate to changes in wave velocity with frequency and bending around obstacles, respectively, rather than the main energy loss mechanism. Composition and shape influence how a wave interacts with a material or boundary, but they’re not the direct processes causing attenuation along the propagation path.