Which statement describes refraction?

Which statement describes refraction?

• A. The energy wave is bent as it strikes an interface between two different tissue layer densities.
• B. The energy wave may be partially or fully reflected by the tissue layer.
• C. Energy can be absorbed by one layer reducing energy to deeper tissues.
• D. Any energy that is not reflected or absorbed will continue to pass through the medium.

Answer: (A)

Refraction is the bending of a wave as it passes from one medium into another with a different propagation speed. In tissue, speed changes with density and elasticity, so when the wave crosses an interface between two tissues, its direction shifts. The statement that the energy wave is bent at an interface between two different tissue densities captures this directional change caused by the speed difference. The other ideas describe related but distinct phenomena: reflection is the wave bouncing back from the interface, absorption is energy taken up by the tissue and not transmitted, and simple transmission without a change in direction describes a case where the wave continues straight through. Refraction specifically means the path bends due to the change in speed at the boundary.

Refraction is the bending of a wave as it passes from one medium into another with a different propagation speed. In tissue, speed changes with density and elasticity, so when the wave crosses an interface between two tissues, its direction shifts. The statement that the energy wave is bent at an interface between two different tissue densities captures this directional change caused by the speed difference.

The other ideas describe related but distinct phenomena: reflection is the wave bouncing back from the interface, absorption is energy taken up by the tissue and not transmitted, and simple transmission without a change in direction describes a case where the wave continues straight through. Refraction specifically means the path bends due to the change in speed at the boundary.