Refraction in ultrasound involves waves doing what as they cross an interface?

Refraction in ultrasound involves waves doing what as they cross an interface?

• A. Passing through the interface but changing direction due to density differences
• B. Reflecting back completely
• C. Speeds up without changing direction
• D. Stopping at the interface

Answer: (A)

Refraction happens when a ultrasound wave crosses an interface into a medium where the speed of sound is different, so the transmitted wave changes direction. The speed difference comes from the tissue’s density and elastic properties, which alter how fast sound travels in each medium. As the wave hits the boundary, its velocity must adjust in the new medium, and the change in velocity causes the beam to bend according to Snell’s law. Some energy is also reflected at the boundary, but the key point for refraction is the transmitted beam changing direction while continuing on. The other options describe either full reflection, a speed change without bending, or stopping at the interface, none of which capture the bending that defines refraction.

Refraction happens when a ultrasound wave crosses an interface into a medium where the speed of sound is different, so the transmitted wave changes direction. The speed difference comes from the tissue’s density and elastic properties, which alter how fast sound travels in each medium. As the wave hits the boundary, its velocity must adjust in the new medium, and the change in velocity causes the beam to bend according to Snell’s law. Some energy is also reflected at the boundary, but the key point for refraction is the transmitted beam changing direction while continuing on. The other options describe either full reflection, a speed change without bending, or stopping at the interface, none of which capture the bending that defines refraction.