RIU 320 Lecture Notes - Lecture 33: Sound, Refraction, Attenuation Coefficient
6 May 2020
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Document Summary
Refraction, the change in direction of wave propagation when traveling from one medium to another. Refraction is a process associated with transmission and occurs with light waves as well as sound waves. A straight pencil sitting in a glass of water may appear to be bent as a result of refraction. Speed 2 less than speed 1 transmission angle less than incident angle. Derived from reflection information; use law of conservation of energy. Oblique incidence and different speeds required: a pulse of ultrasound propagates in soft tissue, such as the liver. The pulse strikes a soft tissue- soft tissue interfaces with oblique incidence. To what extent is the transmitted beam refracted: the transmitted beam undergoes little to no refraction. A transmitted beam is refracted when the incidence is oblique and the propagation speeds are different. However, because the beam refracted significantly( there was a 20 degree change in direction), the speeds of these two media are very different.
