Module1.2 Flashcards
What are the two material properties that the speed of an ultrasound wave in matter is dependent upon?
Density and compressibility(bulk modulus)
What is the materials having properties that are direction dependent called?
Anisotropic
What is the material independent of direction called?
Isotropic
What is the property that actually distinguishes two media acoustically (not density not bulk modulus)
Acoustic impedance (Z)
What is bulk modulus?
A measure of how difficult it is to transmit the sound wave
OR
The ratio of the change in pressure to the corresponding fractional change in volume
What is the ratio of the mass of a sample of material to its volume?
Density
What is acoustic impedance?
A measure of how difficult it is to transmit a sound wave through a given medium, overcoming the stiffness of the material and the inertia of the vibrating particle
What is acoustic interface?
The boundary between two media with different acoustic impedances
When does reflection and retraction occur?
When sound wave interact with an interface between two acoustic media
What is it called when the ray makes the angle to a line perpendicular to the interface?
Interface normal
What is it called when some of the incident wave is reflected?
Specular reflection
What happens to the wave component that is not reflected at the interface between two media?
Refracted or transmitted
What is Attenuation?
Absorption + scattering
Some of the energy is absorbed while scatter redirects the energy into a different direction compared to incident wave.
Simply,it is the decrease in energy of the wave as measured in the direction of the incident wave
What is reflection coefficient (R) ?
The ratio of the intensity of the reflected wave compared to the intensity of the incident wave and is determined by the acoustic impedances of the two media comprising the two media
What is the transmission coefficient (T)?
The ratio of the intensity of the transmitted wave compared to the intensity of the incident wave
