What is the term for the angle between the reflected sound and a line perpendicular to the media boundary?

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

Answer: (A)

The angle of reflection is defined as the angle between the reflected sound beam and the line drawn perpendicular to the boundary (the normal). This is the measurement used for the reflected ray, and for a smooth interface the law of reflection states that the angle of incidence equals the angle of reflection relative to that normal. In ultrasound, this is the precise term for describing how the reflected beam angles after bouncing off a boundary.

Refraction would involve the beam changing direction as it passes into a new medium, not the reflected ray. Scattering refers to energy spreading in many directions rather than a single reflected angle. Specular reflection describes a mirror-like reflection process, but the question is about the angle itself, which is specifically the angle of reflection.