ARDMS SPI Acoustic Waves and Properties 2

Question 1

Which acoustic parameter is determined solely by the medium through which sound travels?

Accepted Answer

Propagation speed

Answer

Propagation speed depends entirely on the medium's density and stiffness, not on the sound source.

Question 2

If the propagation speed of sound increases while frequency remains constant, what happens to wavelength?

Accepted Answer

Wavelength increases

Answer

Wavelength = propagation speed / frequency, so an increase in speed with constant frequency results in a longer wavelength.

Question 3

The acoustic impedance of a tissue is defined as the product of:

Accepted Answer

Density and propagation speed

Answer

Acoustic impedance (Z) = density (ρ) × propagation speed (c), measured in Rayls.

Question 4

Rarefaction in a longitudinal acoustic wave refers to:

Accepted Answer

A region of decreased particle density

Answer

Rarefaction is the low-pressure, low-density phase of a longitudinal wave where particles are spread apart.

Question 5

Which unit is used to quantify acoustic intensity?

Accepted Answer

Watts per square centimeter (W/cm²)

Answer

Acoustic intensity represents power per unit area and is expressed in W/cm² or mW/cm².

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test