Section 2: Physics of Ultrasound

Note that in the diagram, there is a reflected longitudinal wave (V L1' ) shown.
This wave is reflected at the same angle as the incident wave because the
two waves are traveling in the same material, and hence have the same
velocities. This reflected wave is unimportant in our explanation of Snell's Law,
but it should be remembered that some of the wave energy is reflected at the
interface. In the applet below, only the incident and refracted longitudinal
waves are shown. The angle of either wave can be adjusted by clicking and
dragging the mouse in the region of the arrows. Values for the angles or
acoustic velocities can also be entered in the dialog boxes so the that applet
can be used as a Snell's Law calculator.