Final

Question 1

What do waves transfer from one location to another/

Answer 1

Energy

Question 2

Which of the following terms does not belong?
A. compression
B. region of high density
C. region of high pressure
D. wide molecular spacing

Answer 2

D

Question 3

Variations in all of the following identify specific waves as acoustic waves except:
Pressure
Parameters
Density
Acoustic variables

Answer 3

parameters

Question 4

What kind of waves are soundwaves?

Answer 4

mechanical, longitudinal, pressure waves

Question 5

All of the following are acoustic parameters except:
Pressure
Period
Propagation speed
Frequency

Answer 5

Pressure

Question 6

Which types of waves will exhibit both constructive and destructive interefence?
A. waves of different amplitude
B. a pair of longitudinal waves
C. waves of different frequency
D. out of phase waves

Answer 6

C

Question 7

What units are used to report the pressure of a sound beam?

Answer 7

pascals

Question 8

Which of the following waves is infrasonic?
4 MHz
400 kHz
28 Hz
2 Hz

Answer 8

2 Hz, below 20=infra

Question 9

Which wave is ultrasonic?
400 mHz
4 MHz
28 Hz
2 Hz

Answer 9

4 MHz, greater than 20,000=ultra

Question 10

Which of these is ultrasonic and most useful diagnostically?
400 MHz
4 MHz
2 kHz
200,000 Hz

Answer 10

4 MHz

Question 11

Identify all waves that are inaudible
4 MHz
400 kHz
28 Hz
2 Hz

Answer 11

4 MHz, 400 kHz, 2 Hz

Question 12

Which of the following waves has the longest period?
2 MHz
4,000 Hz
6 Hz
1 kHz

Answer 12

6 Hz

Question 13

Of the four waves whose periods are listed below, which has the highest frequency?
8 s
80 microseconds
8 Ms
800 ks

Answer 13

80 microseconds

Question 14

Of the four waves whose frequencies are listed below, which has the shortest period?
12 kHz
6,000 Hz
205 Hz
1 kHz

Answer 14

12 kHz

Question 15

What parameter is determined by both the source and the medium?

Answer 15

wavelength

Question 16

What two characteristics of a medium determine the speed of sound?

Answer 16

stiffness and density
increased stiffness = increased speed
increased density = decreased speed

Question 17

T or F: If the amplitude of a wave is increased to 3 times its original value, the intensity is increased by 6 times.

Answer 17

False, intensity is proportional to amplitude squared, intensity would increase by a factor of 9

Question 18

T or F: If the power of a wave is halved, the intensity is reduced to 1/4 is original value

Answer 18

False, if power is halved, intensity is halved

Question 19

T or F: Propagation speed increases as frequency increases

Answer 19

False

Question 20

Medium 1 has a density of 9 and a stiffness of 6. Medium 2 has a density of 8 and a stiffness of 6. In which medium will sound travel slower?

Answer 20

Medium 1

Question 21

If the power in a beam is 1 watt and the area is 5 sq cm, what is the beam’s intensity?
5 W/sq cm
1 W/sq cm
0.2 W/sq cm
1 Watt

Answer 21

0.2 W/cm sq

Question 22

If intensity remains the same while the power is doubled, what has happened to the beam area?
A. quadrupled
B. doubled
C. halved
D. unchanged

Answer 22

B

Question 23

A sound beam travels a total of 10 cm in 2 seconds. What is the speed of the sound?
A. 10 cm/sec
B. 2 cm/sec
C. 5 cm/sec
D. 0.2 cm/sec

Answer 23

C. 10 cm/2 s = 5 cm/s

Question 24

T or F: Propagation speed increases as frequency increases

Answer 24

False

Question 25

T or F: Propagation speed increases as frequency decreases

Answer 25

False

Question 26

T or F: Propagation speed does not change as frequency increases

Answer 26

True

Question 27

What is the wavelength of 3 MHz sound in soft tissue? A. 0.51 m B. 0.51 km C. 0.51 mm D. 0.51 nm E. 0.51 micrometers

Answer 27

C

Question 28

What is the wavelength of 2 MHz sound in soft tissue? A. 1.54 mm B. 0.77 mm C. 0.51 mm D. 1.54 km/s E. 3.08 mm

Answer 28

B. 1.54/2 MHz = 0.77

Question 29

Which of the following are considered acoustic variables? A. frequency B. density C. particle motion D. temperature E. period F. pressure

Answer 29

B, C, F

Question 30

Which of the following are considered acoustic parameters? A. frequency B. density C. distance D. pressure E. period

Answer 30

A, E

Question 31

The effects of tissue on sound waves are called

Answer 31

acoustic propagation properties

Question 32

Which of these values for PRF would have the longest PRP? A. 2 kHz B. 4,000 Hz C. 6 Hz D. 1 kHz

Answer 32

C

Question 33

Which of the following four waves has the highest PRF based on PRP? A. 8 s B. 80 ms C. 5 ms D. 400 ks

Answer 33

C

Question 34

Which of these pulses with PRF listed below has the shortest PRP? A. 12 kHz B. 6000 Hz C. 20 kHz D. 1 kHz

Answer 34

C

Question 35

Four waves have PRPs as listed. Which wave has the lowest PRF? A. 8 s B. 80 microseconds C. 8000 ns D. 800 ms

Answer 35

A

Question 36

T or F: Two waves can have identical PRFs, even if their PRPs are different

Answer 36

False

Question 37

T or F: Two waves can have identical PRFs even if their periods are different

Answer 37

True

Question 38

T or F: Two waves can have identical PRFs, even if their frequencies are different

Answer 38

True

Question 39

T or F: PRF and PRP are determined only by imaging depth.

Answer 39

True

Question 40

If all other factors remain unchanged, what happens to duty factor when the PRF increases?

Answer 40

increases

Question 41

If all other factors remain unchanged, what happens to the duty factor when imaging depth increases?

Answer 41

Decreases

Question 42

If all other factors remain the same, what happens to the duty factor when the PRP increases?

Answer 42

Decreases

Question 43

If all other factors remain unchanged, what happens to the duty factor when the sonographer uses a new transducer with a longer pulse duration?

Answer 43

increases

Question 44

What is the duty factor if the pulse duration is 1 microsecond and the PRP is 1 ms? A. 100% B. 0.1 C. 0.01 D. 0.001

Answer 44

D

Question 45

Which of the following terms does not belong? A. high duty factor B. shallow imaging C. low PRF D. short PRP

Answer 45

C