# Ch. 2 Flashcards

1
Q

______ is the amount of complete cycles per second.

a. wavelength
b. period
c. frequency
d. propagation speed

A

c. frequency

2
Q

If frequency increases, each cycle (period) _______.

a. increases
b. decreases
c. remains unchanged
d. doubles

A

b. decreases

3
Q

Wavelength is the ______ over which one cycle occurs.

a. time
b. length
c. area
d. power

A

b. length

4
Q

Propagation speed is the speed at which a wave ______ through a medium.

a. cycles
b. refracts
c. travels
d. reflects

A

c. travels

5
Q

Stiffer media have _____ sounds speeds.

a. lower
b. higher
c. stiffness does not change the prop. speed
d. sound cannot propagate through the stiffer media

A

b. higher

6
Q

Frequency _______ wavelength.

a. is directly proportional to
b. is inversely proportional to
c. is equal to
d. has no bearing on

A

b. is inversely proportional to

7
Q

Ultrasound pulses contain a range of frequencies called the ________.

a. fundamental frequencies
b. duty factor
c. pulse repetition frequencies
d. bandwidth

A

d. bandwidth

8
Q

Pulsed ultrasound consists of _____ separated by ______ of time.

a. frequencies; cycles
b. pulses; cycles
c. pulses; gaps
d. cycles; pulses

A

c. pulses; gaps

9
Q

Pulse repetition frequency (PRF) refers to the _____ of pulses occurring in one second.

a. speed
b. number
c. type
d. cycle

A

b. number

10
Q

All of the following are acoustic variables except ______:

a. pressure
b. density
c. compression
d. particle vibration

A

c. compression

11
Q

The fraction of time that pulsed ultrasound is on is called ____.

a. pulse repetition period
b. duty factor (DF)
c. period
d. spatial pulse length

A

b. duty factor (DF)

12
Q

As sound travels, the reduction in amplitude and intensity of the wave is called _____.

a. scattering
b. attenuation
c. absorption
c. reflection

A

b. attenuation

13
Q

What would be the frequency for a .22 mm wavelength in soft tissue?

a. 5.0 MHz
b. 7.0 MHz
c. 7.5 MHz
d. 3.5 MHz

A

b. 7.0 MHz

14
Q

What is the pulse duration of a four-cycle pulse in a period of 0.5 us?

a. 0.2 us
b. 2.0 us
c. 1.25 us
d. .125 us

A

b. 2.0 us

15
Q

skip

A

skip

16
Q

The velocity of sound in human soft tissue is assumed to be a constant. If you employ a 7.5 MHz transducer, what is the wavelength of the sound?

a. .11 mm
b. .20 mm
c. .025 mm
d. 1.1 mm

A

b. .20 mm

17
Q

20 kHz is equal to ____ Hz.

a. 200
b. 2000
c. 20,000
d. 200,000

A

c. 20,000

18
Q

1000 Hz is equal to ___ kHz.

a. 1
b. 10
c. 1000
d. .1

A

a. 1

19
Q

What is the attenuation coefficient for a 5.0 MHz transducer in soft tissue?

a. .25 dB/cm
b. .1 dB/cm
c. 2.5 dB/cm
d. 10 dB/cm

A

c. 2.5 dB/cm

20
Q

At what depth does a 3.0 MHz transducer have an attenuation of 9 dB?

a. 6.0 mm
b. .6 cm
c. 6.0 cm
d. .6 mm

A

c. 6.0 cm

21
Q

What is the attenuation of a 7.5 MHz transducer at a depth of 20 mm?

a. 7.5 dB
b. 5.0 dB
c. .53 dB
d. 75 dB

A

a. 7.5 dB

22
Q

If beam power increases, intensity ______.

a. increases
b. decreases
c. doubles
d. remains unchanged

A

a. increases

23
Q

Attenuation increases with increasing _______.

a. wavelength
b. frequency
c. power
d. pressure

A

b. frequency

24
Q

For perpendicular incidence, the incidence angle is _______.

a. 50
b. 10
c. 90
d. 0

A

d. 0

25
Q

The pulse repetition frequency is the number of pulses that occur in a single ______.

a. microsecond
b. second
c. millisecond
d. pulse

A

b. second

26
Q

Calculate the pulse duration for a 3.0 MHz transducer in soft tissue with a four-cycle pulse.

a. 1.2 us
b. 1.3 us
c. 12 us
d. 13 us

A

b. 1.3 us

27
Q

Continuous wave (CW) Doppler has a duty factor of _____ %.

a. 1.0
b. .10
c. 100
d. 10

A

c. 100

28
Q

What is the spatial pulse length of a four-cycle pulse with a wavelength of .1 mm?

a. 4.0 mm
b. .4 cm
c. .4 mm
d. 40 mm

A

c. .4 mm

29
Q

Duty factors for sonography are typically in the range of _____ %.

a. .1 - 1.0
b. .5 - 2.0
c. 25 - 50
d. 90 - 11

A

a. .1 - 1.0

30
Q

Impedance is equal to density multiplied by ______.

a. propagation speed
b. wavelength
c. path length
d. stiffness

A

a. propagation speed

31
Q

The unit for impedance is _____.

a. W/cm^2
b. dB/cm
c. watt
d. rayl

A

d. rayl

32
Q

The even harmonics of 2 MHz are _____MHz.

a. 2 , 4 , 6
b. 4, 8 , 12
c. 2 , 4 , 8
d. 4 , 6 , 8

A

b. 4 , 8 , 12

33
Q

If the propagation speed through the second medium is greater than through the first medium, the transmission angle is _____.

a. less than the incidence angle
b. equal to the incidence angle
c. greater than the incidence angle
d. unrelated to teh incidence angle

A

c. greater than the incidence angle

34
Q

The distance to the reflector (D) in soft tissue with a round-trip time of 39 us is _____.

a. 3 mm
b. 3 cm
c. 13 mm
d. 13 cm

A

b. 3 cm

35
Q

What does 3 dB of attenuation mean?

a. one half the original intensity
b. one third the original intensity
c. Three decibels more than the original intensity
d. increasing amplitude

A

a. one half the original intensity

36
Q

Which of the following is not a term used to describe continuous wave ultrasound?

a. pulse duration
b. frequency
c. wavelength
d. propagation speed

A

a. pulse duration

37
Q

Lateral position errors occur on an image due to sound _____.

a. reflection
b. attenuation
c. refraction
d. transmission

A

c. refraction

38
Q

The proportion of intensity to amplitude is _____.

a. tripled
b. halved
c. squared

A

c. squared

39
Q

Attenuation encompasses ______.

a. absorption
b. scattering
c. reflection
d. all of the above

A

d. all of the above

40
Q

What units are used to quantify attenuation?

a. unitless
b. dB/cm
c. dB
d. rayls

A

c. dB

41
Q

If intensity reflection coefficient increases, intensity transmission coefficient _____/

a. decreases
b. increases
c. remains unchanged
d. is equal to the intensity reflection coefficient

A

a. decreases

42
Q

For perpendicular incidence and equal impedances between media, there is no ____ and the ______ intensity equals the incident intensity.

a. transmission; reflected
b. refelction; transmitted
c. transmission; transmitted
d. refelction; reflected

A

b. reflection; transmitted

43
Q

The distance to a reflector in soft tissue is 15 cm. What is the round-trip time to this depth?

a. 19.5 us
b. 195 us
c. 1.15 us
d. 11.5 us

A

b. 195 us

44
Q

In oblique incidence, the ______ and ______ angles are always equal.

a. transmitted; reflected
b. normal; transmitted
c. incidence; reflection
d. incidence; transmitted

A

c. incidence; reflection

45
Q

The liquid suspensions that have been developed can be injected into the circulation intravenously to increase _____.

a. wavelength
b. propagation speed
c. impedance
d. echogenicity

A

d. echogenicity

46
Q

If an echo returns 104 us after a pulse was emitted by a transducer, at what depth is the structure that produced the echo located?

a. .8 mm
b. 80 cm
c. 8.0 mm
d. 8.0 cm

A

d. 8.0 cm

47
Q

In oblique incidence, when the propagation speeds on either side of the boundary are different, which incidence is most likely to occur?

a. transmitted
b. refracted
c. reflected
d. attenuated

A

b. refracted

48
Q

Intensity is equal to the power of a wave divided by the ___ over which the power is spread.

a. diameter
c. area
d. width

A

c. area

49
Q

Amplitude is the maximum variation that occurs in an acoustic ___.

a. frequency
b. medium
c. variable
d. propagation speed

A

c. variable

50
Q

Which of the following determines how fast images are generated?

a. pulse duration
b. duty factor
c. pulse repetition frequency
d. pulse repetition period

A

c. pulse repetition frequency