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Flashcards in Test One Deck (25):
0

Ultrasound is defined as sound with a frequency....

greater than 20,000Hz or 0.02 MHz

1

wavelength is inversely proportional to...

period
density
intensity
frequency

frequency

2

Wave mechanic studies reveal that ultrasound is all of the following except:
electromagnetic wave
compression wave
mechanical wave
longitudinal wave

electromagnetic wave

3

What determines the initial amplitude of an ultrasound wave:

the transducer
the medium through which sound travels
Both
neither

the transducer

4

What determines the period of an ultrasound wave?

the transducer
the medium through which sound travels
both
neither

the transducer

5

what is characteristic of acoustic waves with frequencies exceeding 20,000 hz when compared with waves having frequencies less than 20,000Hz?

travel more effectively through soft tissue
travel more rapidly
attenuate less when traveling in soft tissue
humans cannot hear them

humans cannot hear them

6

what is the approximate frequency that has a wavelength of 0.4 mm in soft tissue?

3.0 kHz
3.0 MHz
3.8 kHz
3.8 MHz

3.8 MHz

7

What is the highest concentration of tissue molecules?

compression
excitation
refraction
rarefaction

compression

8

What is the period of soft tissue for a 5 MHz frequency?

o.20 sec
1.3 micro sec
0.20 microsec
2.0 microsec

0.20 micro sec

9

What is the propagation speed of a 5 MHz sound wave in soft tissue?

1,450 m/s
1,540 km/s
1.750 m/s
1.54 mm/us

1.54 mm/us

10

What is the range of frequencies emitted by transducers in ultrasonic imaging?

1-3 MHz
1 to 1000 KHz
-10,000 to +10,000 Hz
2,000,000 to 10,000,000 Hz

2,000,000 to 10,000,000 Hz

11

What is the range of periods commonly found in waves produced by ultrasound systems?

0.1 to 1.0 usec

12

What is the reciprocal of 100?

0.01

13

What is the speed of sound in soft tissue?

1.54 mm/us

14

what is the term for any sound that is less than audible sound?

infrasound

15

what is the wavelength of 10 MHz sound in soft tissue?

.77mm
.15mm
1.54 mm
10mm

.15mm

16

What is the wavelength of a 2 MHz sound in soft tissue?

0.77 mm
cannot be determined
1.54 mm
2 mm

0.77 mm

17

What term describes the number of cycles that an acoustic variable completes in a second?

period
frequency
pulse repetition period
variable rate

frequency

18

what two properties establish sound's propagation sped in a given medium?

elasticity and stiffness
stiffness and impedance
conductance and density
density and stiffness

density and stiffness

19

When an acoustic wave travels through a medium, the tissue molecules change concentration. what is the highest level of concentration?

compactness
compression
excitation
ionization
rarefaction

compression

20

when the elasticity of a medium is high, the _______is high

stiffness
propagation speed
compressibility
reflectivity

compressibility

21

When you multiply reciprocals the answer is:

1

22

when your patient asks you how much longer the US test will take, his voice is in the audible range. Which of the following is in the audible range:

100 Mhz
10 kHz
10 Hz
10,000 MHz

10 kHz

23

Which of the following best describes sound waves?

transverse, pressure waves
transverse, longitudinal waves
longitudinal, out of phase waves
longitudinal pressure waves

longitudinal pressure waves

24

Which of the following cannot be considered a unit of frequency:

per day
cycles per second
Hz
Hertz
Cycles

Cycles