ARDMS Ultrasound Physics & Instrumentation Practice Exam 2026 - Free Ultrasound Practice Questions and Study Guide

The term that describes the change in the direction of sound waves when they encounter different tissue types is refraction. Refraction occurs because sound waves travel at different speeds in different media. When a sound wave passes from one type of tissue to another with a different acoustic impedance, its speed changes, resulting in a change in direction. This bending of the wave can significantly affect image quality and the accuracy of measurements in ultrasound imaging.

Reflection refers to the bouncing back of sound waves when they hit a boundary between two tissues, while diffraction describes the spreading of sound waves when they encounter an obstacle or aperture. Displacement is not a defined term in relation to ultrasound wave behavior. Understanding refraction is crucial for ultrasound technicians, as it impacts the interpretation of ultrasound images and the positioning of the transducer for optimal results.