What term describes the bending of the sound beam?

What term describes the bending of the sound beam?

• A. Axial displacement of a reflector
• B. Multiple images of a single reflector
• C. Refraction
• D. Enhancement distal to a reflector

Answer: (C)

Refraction is the bending of the sound beam as it crosses a boundary between tissues with different propagation speeds at an angle. When the beam hits the interface obliquely, the change in speed between media causes the wavefront to tilt, so the path of the beam changes direction. This idea is described by Snell’s law and explains why echoes can appear shifted to the side from where you’d expect if the beam traveled in a straight line. The other phenomena refer to different effects: axial displacement involves depth errors along the beam, multiple images come from reflections or reverberation, and enhancement distal to a reflector relates to changes in brightness behind a structure due to attenuation, not beam bending.

Refraction is the bending of the sound beam as it crosses a boundary between tissues with different propagation speeds at an angle. When the beam hits the interface obliquely, the change in speed between media causes the wavefront to tilt, so the path of the beam changes direction. This idea is described by Snell’s law and explains why echoes can appear shifted to the side from where you’d expect if the beam traveled in a straight line. The other phenomena refer to different effects: axial displacement involves depth errors along the beam, multiple images come from reflections or reverberation, and enhancement distal to a reflector relates to changes in brightness behind a structure due to attenuation, not beam bending.