Which term describes surfaces that reflect sound in only one direction and are angle dependent?

Which term describes surfaces that reflect sound in only one direction and are angle dependent?

• A. Reflection angle
• B. Refraction
• C. Scattering
• D. Specular reflections

Answer: (D)

Specular reflections describe surfaces that are smooth on the scale of the ultrasound wavelength and reflect sound in a single, predictable direction. When the boundary is smooth, the incident angle equals the reflection angle, so the echo is directed back toward the transducer if the geometry lines up. This angle-dependent, mirror-like behavior makes the reflected signal strong and well-defined when the beam hits the boundary at the right angle. If the surface is rough or irregular at the wavelength scale, the energy is scattered in many directions, producing diffuse echoes rather than a single, directional return. Refraction, by contrast, involves bending of the wave as it passes into a different medium and does not describe a single back-reflected ray. A reflection angle is the measured result of specular reflection, not a separate type of reflection.

Specular reflections describe surfaces that are smooth on the scale of the ultrasound wavelength and reflect sound in a single, predictable direction. When the boundary is smooth, the incident angle equals the reflection angle, so the echo is directed back toward the transducer if the geometry lines up. This angle-dependent, mirror-like behavior makes the reflected signal strong and well-defined when the beam hits the boundary at the right angle. If the surface is rough or irregular at the wavelength scale, the energy is scattered in many directions, producing diffuse echoes rather than a single, directional return. Refraction, by contrast, involves bending of the wave as it passes into a different medium and does not describe a single back-reflected ray. A reflection angle is the measured result of specular reflection, not a separate type of reflection.