sound chapter 2 flashcards

These flashcards review key concepts related to sound waves and their behavior in the context of medical imaging as discussed in the lecture.

What are sound waves in the context of medical imaging?

Sound waves are mechanical waves that carry energy, including heat, sound, magnetic, and light.

What is the definition of a longitudinal wave?

In a longitudinal wave, particles move in the same direction as the waves propagate.

What is a transverse wave?

The wave is moving from left to right, the particles in the wave moving up and down. (Ocean wave)

How do transverse waves differ from longitudinal waves?

In transverse waves, particles move perpendicular to the direction in which the wave propagates.

What are in phase waves?

In phase waves are pairs of waves with peaks (max values) that occur at the same time and location.

What is destructive interference?

Destructive interference occurs when out-of-phase waves create a single wave with less amplitude compared to one of the waves in the pair.

What happens during constructive interference?

Constructive interference occurs when in-phase waves combine to create a single wave of greater amplitude.

What does it mean when two waves are out of phase?

Out of phase waves do not align, occurring at different points in time.

What is the result of interference between waves of different frequencies?

When waves of different frequencies interfere, there will be both constructive and destructive interference at different times.

What is acoustic propagation properties?

The effects of the medium upon the sound wave.

What is biologic effects?

The effects of the sound wave upon the biologic tissue through which it passes.

What are acoustic variables identify sound waves? list the units

Acoustic Variables are pressure (pascals/ Pa) , density (kg/cm³) , and distance (cm/mm).

What are the acoustic parameters that describe a sound wave?

Period

Frequency

Amplitude

Power

Intensity

Wavelength

Propagation Speed

Which of the following terms does not belong with the others?

Wide molecular spacing

All of the following are true of sound waves except

Sound waves are longitudinal, not transverse.

All of the following are acoustic parameters except

Pressure is an acoustic variable, not parameter

What best describes sound waves?

Longitudinal, pressure waves

Two waves are traveling in a medium and arrive at a location at the same time. What events take place?

interference

What type of waves will exhibit both constructive and destructive interference?

both constructive and destructive interference occurs with waves with different frequencies

What units are used to report the pressure of a sound beam?

Pressure is reported with units of Pascal/ Pa

Acoustic variables, allow us to determine which waves are sound waves in, which are not? (T/F)

True

Acoustic parameters are used to describe the features of sound waves. (T/F)

true

What do mechanical waves require?

Medium

What do electromagnetic waves require?

Medium and space

What type of wave is a mechanical wave

Longitudinal wave and transverse

What type of wave is an electromagnetic wave?

Transverse Wave

What happens to particle motion during compression

They squeeze together, high density, and high pressure.

What happens to particle motion during rarefaction?

They pull apart, low density, and low pressure.

What is the definition of Period in ultrasound?

Period is the time it takes for a wave to complete a single cycle, typically measured in units of time such as microseconds (\mu s).

How is Frequency defined and what are its units?

Frequency is the number of cycles that occur in one second, measured in units of Hertz (Hz).

What is the mathematical relationship between Frequency (f) and Period (T)?

They are inversely related and reciprocals; f \times T = 1.

Which parameters are determined by the sound source only?

Period, Frequency, Amplitude, Power, and Intensity are determined by the sound source.

What is the definition of Wavelength?

Wavelength is the distance or length of one complete cycle.

What determines the Propagation Speed of a wave?

Propagation speed is determined only by the medium through which the sound is traveling.

How does stiffness affect the speed of sound?

Stiffness and speed are directly related; as a medium becomes stiffer, the speed of sound increases.

How does density affect the speed of sound?

Density and speed are inversely related; as a medium becomes more dense, the speed of sound decreases.

What is the frequency range for audible sound?

Audible sound ranges from 20 Hz to 20,000 Hz (20 kHz).

What is the frequency of Ultrasound?

Ultrasound is any sound with a frequency greater than 20,000 Hz (20 kHz).