Key terms Test1

Question 1

graphs

Answer 1

are a way to display information

graphs contain two axies:

Horizontal axis, Vertical axis

Question 2

Horizontal axis

Answer 2

x-axis, runs side to side

Question 3

Vertical axis

Answer 3

y-axis, runs up and down

Question 4

Directly related

Answer 4

two items are associated with each other

when one increases, the other increases

Question 5

proportional

Answer 5

two items are associated with each other, but their relationship is not specified

Question 6

inversely related

Answer 6

two items are associated with each other

when one item increases, the other decreases

Question 7

reciprocal

Answer 7

special type of inverse relationship

when the two items are multiplied together the result is one

Question 8

units

Answer 8

assigned to numerical values

can be units of length, area, volume, weight, time, etc

Question 9

increase by a factor

Answer 9

means to multiply

Question 10

decrease by a factor

Answer 10

means to divide

Question 11

conversions

Answer 11

changing from one unit to another

Question 12

powers of ten

Answer 12

a number in scientific notation

Question 13

metric system:

10⁹, 10⁶, 10³, 10², 10¹

10^-1, 10^-2, 10^-3, 10^-6, 10^-9

Answer 13

giga, mega, kilo, hecto, deca

deci, hundredth, thousandth, millionth, billionth

Question 14

complimentary units

Answer 14

pairs:

giga-nano, mega-micro, kilo-milli, hecto-centi, deca-deci

Question 15

sound waves:

mechanical, longitudinal

Answer 15

mechanical-can not travel through a vacuum, needs a medium to travel through

longitudinal-travels in a straight line

Question 16

acoustic propagation properties

Answer 16

the effects of the medium upon the sound wave

Question 17

biological effects

Answer 17

the effects of the sound wave upon the tissue it passes through

Question 18

acoustic variables

Answer 18

pressure

density

distance

Question 19

acoustic parameters

Answer 19

period

frequency

amplitude

power

intensity

wavelength

propagation speed

Question 20

transverse waves

Answer 20

particles move perpendicular to the direction the wave moves

Question 21

longitudinal waves

Answer 21

particles move in the same direction the wave moves

Question 22

In phase waves

Answer 22

peaks and troughs occur at the same time

Question 23

Out of phase waves

Answer 23

peaks and troughs occur at different times

Question 24

interference

Answer 24

multiple waves arriving at the same location combining to form a single wave

Question 25

constructive interference

Answer 25

in-phase waves combine to create one larger wave

Question 26

destructive interference

Answer 26

out-of phase waves combine to create one smaller wave, the two waves may cancel each other out

Question 27

period

Answer 27

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

units: units of time

Question 28

frequency

Answer 28

number of cycles that occurs in one second

units: units of per sec (Hz)

Question 29

hertz

Answer 29

1 Hz = 1 cycle/sec

Question 30

amplitude

Answer 30

difference between the maximum value and the average or undisturbed value

units of any of the acoustic variables: pascals, kg/cm³, any distance

Question 31

power

Answer 31

rate of energy transfer

units: Watts

Question 32

intensity

Answer 32

concentration of energy in a sound beam

units: W/cm²

Question 33

wavelength

Answer 33

distance or length of one complete cycle

units: units of length (mm, cm, etc)

Question 34

propagation speed

Answer 34

the rate a sound wave travels through a medium

units: m/sec, mm/µ, or any distance divided by time

Question 35

speed of sound in media

Answer 35

average soft tissue-1,540 m/sec

Question 36

stiffness

Answer 36

ability of an object to resist compression

Question 37

density

Answer 37

relative weight of a material

Question 38

pulsed sound

Answer 38

a series of cycles

Question 39

parameters describing pulsed sound

Answer 39

pulse duration

spatial pulse length

pulse repetition period

pulse repetition frequency

duty factor

Question 40

pulse duration

Answer 40

the time from the start of a pulse to the end of that pulse

units: microseconds, minutes, etc

Question 41

spatial pulse length

Answer 41

the distance from the start of a pulse to the end of that pulse

units: units of distance (mm, m, etc)

Question 42

pulse repetition period

Answer 42

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

(one pulse duration and one listening time)

units: units of time

Question 43

pulse repetition frequency

Answer 43

number of pulses that an ultrasound system transmits into the body each second

units: Hz or per sec

Question 44

duty factor

Answer 44

percentage

amount of time that the machine sends the sound

pulse duration/pulse rep. period x 100 = duty factor

Question 45

shallow imaging

Answer 45

less listening

shorter PRP

higher PRF

higher duty factor

Question 46

deep imaging

Answer 46

more listening

longer PRP

lower PRF

lower duty factor

Question 47

parameters that describe both pulsed and continuous waves

Answer 47

period

frequency

wavelength

propagation speed