Describing Sound Waves

Question 1

describes features of a sound wave

Answer 1

parameters

Question 2

seven parameters that describe sound waves

Answer 2

period 
frequency
amplitude
power
intensity
wavelength
speed

Question 3

time it takes for a wave to vibrate a single cycle

time from start of one cycle to the start of the next cycle

Answer 3

period

Question 4

number of particular events that occur in a specific duration of time

Answer 4

frequency

Question 5

source of a sound wave

Answer 5

ultrasound system and transducer

Question 6

tissue through which sound is traveling

Answer 6

medium

Question 7

Period
Units?
Typical values?
Determined by?
Adjustable?

Answer 7

units of time
0.06 - 0.05 microseconds
sound source only
no

Question 8

Frequency
Units?
Typical values?
Determined by?
Adjustable?

Answer 8

units per second, Hz, hertz
2 - 15 megahertz
sound source
no

Question 9

frequency of infrasound

Answer 9

less than 20 Hz

Question 10

frequency of audible sound

Answer 10

between 20 Hz and 20 kHz

Question 11

frequency of ultrasound

Answer 11

greater than 20 kHz

Question 12

What is the relationship between period and frequency?

Answer 12

inversely related

reciprocals

Question 13

the 3 bigness parameters

Answer 13

intensity
power
amplitude

Question 14

Amplitude 
Units?
Typical values?
Determined by?
Adjustable?

Answer 14

units of pressure (pascals), density (g/cm3), or distance (cm, in)
1 - 3 MPa
sound source
yes

Question 15

measured from the baseline to the maximum or minimum value

difference between max value and undisturbed value of an acoustic variable

Answer 15

amplitude

Question 16

difference between max and minimum values of an acoustic variable
2x the amplitude

Answer 16

peak-to-peak amplitude

Question 17

Power
Units?
Typical values?
Determined by?
Adjustable?

Answer 17

watts
4 to 90 milliwatts
source
yes

Question 18

how are amplitude and power related

Answer 18

power is proportional to amplitude squared

Question 19

Intensity
Units?
Typical values?
Determined by?
Adjustable?

Answer 19

W/cm2
0.01 - 300 W/cm2
sound source
yes

Question 20

how do we calculate intensity (w/cm2)

Answer 20

power (w) / area (cm2)

Question 21

How is intensity related to power?

Answer 21

directly related

Question 22

how is intensity related to amplitude?

Answer 22

intensity is directly related to amplitude squared

Question 23

Wavelength
Units?
Typical values?
Determined by?
Adjustable?

Answer 23

units of length
0.1 - 0.8 mm
source and medium
no

Question 24

What are the similarities / differences between wavelength and period?

Answer 24

they both describe a single cycle in a sound wave
period refers to the time it takes to complete a single cycle
wavelength refers to the length or distance of a single cycle

Question 25

What is the relationship between wavelength and frequency?

Answer 25

inverse

Question 26

Formula used to find the wavelength of a sound wave in soft tissue.

Answer 26

wavelength = 1.54 / frequency

Question 27

Why is wavelength important in diagnostic ultrasound?

Answer 27

shorter wavelengths are greater by high frequencies (high quality image) sonographers should try to use high frequency transducers for this reason

Question 28

``` Speed Units? Typical values? Determined by? Adjustable? ```

Answer 28

mm/us or any distance/time 500 to 4000 m/s medium no

Question 29

speed in soft tissue

Answer 29

1.54 mm/us 1540 m/s 1.54 km/s

Question 30

speed of sound formula

Answer 30

speed = frequency x wavelength

Question 31

2 characteristics that determine the speed of sound in a medium

Answer 31

stiffness | density

Question 32

ability of an object to resist compression

Answer 32

stiffness

Question 33

relative weight of a material

Answer 33

density

Question 34

How does stiffness affect speed?

Answer 34

directly related

Question 35

How does density affect speed?

Answer 35

inversely related

Question 36

another term for stiffness

Answer 36

bulk modulus

Question 37

2 words that describe the opposite of stiff

Answer 37

elasticity | compressibility

Question 38

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

Answer 38

power

Question 39

concentration of energy in a sound beam

Answer 39

intensity

Question 40

distance or length of one complete cycle

Answer 40

wavelength