Textbook Sounds notes (Ch. 2)

Flashcards based on ultrasound physics lecture notes.

How is diagnostic ultrasonography performed?

A transducer emits sound pulses and the reflections are processed into images.

What is sound?

A mechanical wave in which particles in the medium move/vibrate.

Can sound travel through a vacuum?

No it must travel through a medium.

What type of waves are sound waves?

Longitudinal waves.

What are acoustic propagation properties?

The effects of the medium upon the sound wave.

What are biologic effects in ultrasound?

Effects of sound waves on biologic tissue.

When are waves considered in-phase?

When their peaks occur at the same time and location.

When are waves considered out-of-phase?

Their peaks occur at different times.

What is interference?

Multiple beams combine to form a single wave.

What are the three acoustic variables?

Pressure, density, and distance.

What are the units for pressure?

Pascals (Pa).

What are the units for density?

kg/cm³.

What are the units for distance?

cm, feet, mile.

Name the seven acoustic parameters.

Period, Frequency, Amplitude, Power, Intensity, Wavelength, and Propagation speed.

What does constructive interference result in?

Results in a single wave of greater amplitude.

What does destructive interference result in?

Results in a single wave of lesser amplitude.

What occurs when waves of different frequencies interfere?

Interference is constructive when waves are in phase and destructive when out of phase.

Define pressure in the context of acoustic variables.

Concentration of force in an area.

Define density in the context of acoustic variables.

Concentration of mass in a volume.

Define distance in the context of acoustic variables.

Measure of particle motion.