Sound Wave Parameters and Properties

Practice flashcards covering the parameters, definitions, and relationships of sound waves as outlined in the lecture notes.

What are the seven parameters that describe sound waves?

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

What is the relationship between period and frequency?

Period and frequency are reciprocals; as frequency increases, the period decreases and vice versa.

What is defined as 'the rate at which energy is transferred' in sound waves?

Power.

What unit is commonly used to measure frequency?

Hertz (Hz), which represents events per second.

How is amplitude defined in the context of sound waves?

The difference between the maximum value and the average value of an acoustic variable, or between the minimum value and the average value.

What is the typical range of pressure amplitude in imaging?

From 1 million pascals (1 MPa) to 3 million pascals (3 MPa).

What is intensity in relation to sound waves?

The concentration of energy in a sound beam, related to power distributed over an area.

What does the wavelength of a sound wave measure?

The distance or length of one complete cycle of the wave.

What is the typical range of wavelength in soft tissue?

From 0.1 mm to 0.8 mm.

How are intensity and amplitude related?

Intensity is proportional to the square of the amplitude; if amplitude doubles, intensity increases by four times.

What is the speed of sound dependent on?

The type of medium it is traveling through, not affected by the nature of the sound wave.

What factors determine the speed of sound in a medium?

Stiffness and density; stiffness affects speed positively and density negatively.

How does the frequency relate to the wavelength of a sound wave?

Wavelength and frequency are inversely related; as frequency increases, wavelength decreases.

What is period?

Period is the time it takes a wave to vibrate a single cycle, or the time from the start of one cycle to the start of the next cycle.

What is frequency?

Frequency is the number of particular events that occur in a specific duration of time.

What is the frequency spectrum of sound?

Infrasound is less than 20 Hz

Audible sound is between 20 Hz and 20kHz

Ultrasound is greater than 20 kHz

Which of the following waves has the longest period

6 Hz has the longest period. The wave has the lowest frequency has the longest period.

Describe the magnitude of a sound waves.

Amplitude, power, and intensity.

What is amplitude?

The “bigness” of a wave. The difference between the minimum/undisturbed value and the maximum value.

What is power?

The rate of energy transfer or the rate at which is performed. Power, like amplitude, describes the “bigness” of the wave.

What is intensity?

Intensity is the concentration of energy in a sound beam.

Power is related to

Intensity

_______ is related to amplitude squared

Power

________ is related to the amplitude squared.

Intensity

What is wavelength?

The distance or length of one complete cycle. The only parameter that is determined by both the source and the medium.

What is the difference between wavelength and period?

Wavelength refers to the length or distance of a single cycle. Period refers to the time that it takes to complete a single cycle.

Why is wavelength important in diagnostic ultrasound?

Shorter wavelengths are created by high frequency sound. Which produce higher quality image with greater detail.

What is prop. speed?

The rate at which a sound wave travels through a medium.

Sound travels ____ in solids, slower in _____, and the slowest in _____.

Sound travels fastest in solids, slower in liquids, and the slowest in gas.

What two characteristics of a medium affect sound?

Stiffness and density.

How does stiffness affect speed?

Stiffness and speed are directly related.

How does density affect speed?

Density and speed are inversely related.

What other terms describe stiffness?

Bulk modulus is the same as stiffness, elasticity and compressibility.

When density increases what happens to the speed?

It decreases.