Physics

Front 1

Sound waves are characterized by a number of parameters. Name them

1-7

Back 1

1. Period 2. Frequency. 3. Amplitude 4. Power. 5. Intensity. 6. Wavelength 7. Proagation speed

Front 2

_____ refers to the maximum variation of particle displacement, particle density, or acoustic pressure of a sound wave.

Back 2

Amplitude

Front 3

_______ refers to the distance occupied by one complete cycle.

Back 3

Wavelength

Front 4

______ is the measure of time taken for one complete wave cycle to occur.

Back 4

Period

Front 5

Amplitudes measurement is dependent upon the acoustic variable being measured. The units for pressure are expressed as _____, the units for distance are ______, the units for density is ______.____

Back 5

Pascal (Pa)

mm, cm, or m

g/cm^3

Front 6

_____ refers to the number of cycles that pass a given point per second or the number of cycles per second.

Back 6

Frequency

Front 7

_______ refers to the rate at which sound waves propagate through a medium.

Back 7

Propagation speed or speed of sound

Front 8

Propagation speed is measured in units of distance per time such as _____, ________

Back 8

m/s or cm/s

Front 9

Period and frequency are _____. When multiplied together they equal 1 frequency

Back 9

Reciprocal

Front 10

Frequency has a spectrum of sound. Infrasound had a frequency of _______. Audible sound has a frequency of _____ to _____. Ultrasound is greater than _______.

Back 10

Less than 20Hz

Between 20Hz and 20 kHz

Greater than 20 kHz

Front 11

As frequency increases, period ______.

Back 11

Decreases

Front 12

Which of the following waves is infrasonic?

A. 400 mHz

B. 4 MHz

C. 28 Hz

D. 2 Hz

Back 12

D. 2 Hz

Front 13

What range is diagnostic sonography?

Back 13

1-5 MHz

Front 14

The three bigness parameters are ____, _____, ______.

Back 14

Amplitude

Power

Intensity

Front 15

______ is the rate of energy transfer or rate at which work is performed.

Back 15

Power

Front 16

_____ has units of watts.

Back 16

Power

Front 17

Power _____ as sound propagates through the body.

Back 17

Decreases

Front 18

The rate at which power decreases as sound propagates depends on the characteristics of the _____ and the wave.

Back 18

Medium

Front 19

Power is proportional to the waves amplitude ______.

Back 19

Squared

Front 20

______ is the concentration of energy into a sound beam.

Back 20

Intensity

Front 21

To calculate intensity, divide the beams power by the beams _____ _____ area.

Back 21

Cross sectional

Intensity (W/cm^2) = power (W) divided by area (cm^2)

Front 22

Wavelength is the only parameter determined by _____

Back 22

Both the sound source and the medium.

Front 23

Can the wavelength be adjusted by sonographer?

Back 23

No

Front 24

______ is the distance of one complete cycle.

Back 24

Wavelength

Front 25

What is the wavelength of 1 MHz sound in soft tissue?

Back 25

1.54 mm

Front 26

Wavelength is _____ related to frequency. As frequency increases, wavelength ______. Wavelength

Back 26

Inversely

Decreases

Front 27

Wavelength is important in ultrasound because

Back 27

Shorter wavelength create higher frequencies which produces a higher quality image

Front 28

To find the wavelength of a sound wave in soft tissue, you must divide the wavelength 1.54 mm by the _____ in MHz.

Back 28

Frequency

Example: 2 MHz of frequency

1.54/2= 0.77 mm

Front 29

______ is the rate at which a sound wave travels through a medium.

Back 29

Propagation speed or speed

Front 30

Speed is measured in units of _______.

Back 30

Meters per second

mm/us or m/s

Front 31

Speed is determined by the _____

Back 31

Medium

Front 32

Speed is not affected by the nature of the sound wave, all sound regardless of frequency, travels at the same speed through any specific medium. So a 5MHz and a 3 MHz frequency travels at the same ____ ____ in the SAME medium.

Back 32

Propagation speed

Front 33

Wavelength depends on frequency and propagation speed. The relationship between the three is that wavelength is equal to_____ divided by ______. Propagation speed

Back 33

Propagation speed

Frequency

Front 34

Propagation speed is determined by the medium, primarily it's ________.

Back 34

Stiffness

Front 35

Stiffness is the resistance of a material to compression. Stiffness is inverse to _____.

Back 35

Compressibility

Front 36

Compressible material such as a sponge has low stiffness, and a stiff (hard) material such as a rock has low _____.

Back 36

Compressibility

Front 37

Stiffer media have _____ sound speeds

Back 37

Higher

Front 38

Propagation speeds are higher in ______ and lowest in_____.

Back 38

Solids

Gases

Front 39

____ are even and odd multiples of fundamental frequencies

Back 39

Harmonics

Front 40

With CW ultrasound, cycles repeat ______ , while pulsed ultrasound consists of pulses separated by gaps in ____. A pulse is a few ____ of ultrasound.

Back 40

Indefinitely

Time

Cycles