Final Exam: Exams 1-5

Which of the following best describes waves A and C?

Which of the following intensities is the most important for thermal bio effects?

Which of the following best describes line A?

_____ intensity is the lowest intensity in bioeffects.

Which of the following best describes line E?

How many Hertz is 3 MHz?

SAPA is an abbreviation for?

Which of the following best describes line C?

_____ intensity is the relevant intensity with respect to tissue heating.

(Intensity) Pulse is referring only to____.

Which of the liens above A, B, or C is most likely to be determined by the source and the medium?

Which of the following best describes line C?

Which of the following statements is correct regarding intensities.

_____ intensity is the highest intensity in bioeffects.

Which of the following does not apply as a key word relating to intensity.

SPTP is related to tissue cooling?

Which of the following best describes line F?

_____ is the time from the start of a pulse to the end of the pulse.

Which of the lines above A, B, or C is most likely to be the reciprocal of frequency?

Which of the following best describes line B?

Intensities may not be reported in various ways in relations to bioeffects.

Which of the following best describes waves D and E?

Which of the following best describes waves A and B?

Which of the following best describes line D?

Which of the following best describes waves B and C?

Which of the following best describes line B?

Which of the following best describes line D?

Which of the following best describes waves A and E?

Which of the following best describes line A?

How many liters are in 80 ml in fluid?

Which of the following best describes line A?

Intensities may not be reported in various ways with respect to time and space.

SPTA is an abbreviation for?

The power of a system is a 100% and this is 0 dB. The system is changed to -6 dB. What is the system’s power?

A. 25%
B. 100%
C. 75%
D. 50%

What are the units of attenuation?

A. decibels
B. pascals
C. rayl
D. watts

A signal’s power increases from 1 watt to 100 watts. How is this expressed in decibels?

A. 20 dB
B. 10 dB
C. 40 dB
D. 6 dB

Attenuation in the lung tissue is ____ (less than, greater than, the same as) soft tissue.

A. greater than
B. less than
C. the same as
D. unable to solve problem

All of the following apply to Intensity?

A. all of the above
B. is the concentration of the power in a beam
C. it is a key parameter for bioeffects
D. is not uniform across a sound beam, nor through time, with pulsed ultrasound

Every 10 dB means that the intensity will?

A. increase ten times
B. increase three times
C. decrease ten times
D. decrease three times

What type of incidence is there between 3 and 4?

A. oblique
B. refraction
C. reflection and transmission occurs
D. transmission only

As path length increases, attenuation of US in soft tissue ______?

A. increases
B. decreases
C. remains the same
D. more than one option is applicable

dB is mathematical representation with a _____ scale.

A. logarithmic
B. longitudinal
C. division
D. multiplicative

What is 10^-6 seconds / 10^-3 seconds?

A. 10^-3
B. 10^+3
C. 10^-9
D. 10^-6

A reduction of intensity to one-half of its original value is?

A. -3 dB
B. -6 dB
C. +3 dB
D. +6 dB

Which is better to use while examining a carotid artery, a 7.5 or 3.0 MHz transducer?

A. 7.5 MHz
B. 3.0 MHz
C. both the 7.5 MHz and 3.0 MHz
D. none of the above

What property has units of rayls? How is it determined?

A. impedance
B. attenuation
C. intensity
D. none of the above

An ultrasound system operating at 100% power and the power setting is 0 dB. What would the power setting be when the system is operating at 10% power?

A. -10 dB
B. -90 dB
C. 50 dB
D. -3 dB

A 3 MHz sound beam travels 7 cm in a medium. The total attenuation is 5 dB. How much attenuation will a 6 MHz sound beam undergo when traveling 3.5 cm in the same medium?

A. 5 dB
B. 2 dB
C. 7 dB
D. cannot be determined

What process occurs as the US passes through all media?

A. attenuation (scattering, absorption, reflection)
B. attenuation (absorption and reflection)
C. attenuation (scattering, absorption, and reflection)
D. attenuation (scattering, backscatter, and reflection)

A sound wave, with an intensity of 50 W/cm², strikes a boundary and is totally reflected. What is the intensity reflection intensity?

A. 50 W/cm²
B. 25 W/cm²
C. 100%
D. 0%

A 3 MHz sound beam travels 10 cm, 6 cm in medium A and 4 cm in medium B. The total attenuation is 14 dB. If the sound beam attenuated 4 dB in medium A, then how much attenuation occurred in medium B?

A. 10 dB
B. 2 dB
C. 14 dB
D. cannot be determined

Attenuation in air is ______ than soft tissue.

A. much greater than
B. greater than
C. less than
D. much less than

Every 3 dB means that the intensity will?

A. double
B. quadruple
C. decrease by 2
D. decrease by 4

Which of the following waves will have the shortest wavelength?

A. high frequency traveling in a slow medium
B. high frequency traveling in a fast medium
C. low frequency traveling in a fast medium
D. low frequency traveling in a slow medium

What is the log of 100?

A. log of 100 is 2
B. log of 100 is 3
C. log of 100 is 1
D. log of 100 is 1000

An ultrasound system is operating at 100% power and the power setting is 0 dB. What would the power setting be when the system is operating at 25% power?

A. -6 dB
B. -75 dB
C. 50 dB
D. -3 dB

A drop in intensity to one-quarter of its original value is?

A. -6 dB
B. -3 dB
C. +6 dB
D. +3 dB

As the path length increases, the attenuation coefficient of US in soft tissue _____.

A. remains the same
B. greater than
C. less than
D. much less than

True or False. Acoustic impedance does not equal density x propagation speed.

There is normal incidence between the sound wave and the boundary between media 1 and media 2. What happens at the boundary between media 1 and 2.

A. reflection and transmission occurs
B. refraction
C. reflection
D. oblique incidence

-10 dB means that the intensity is reduced to ______ of its original value.

A. one-tenth
B. one-fourth
C. a quarter
D. one-fifth

A 3 MHz sound beam travels through two media. It attenuates 5 dB in medium A and 6 dB in medium B. What is the total attenuation that the sound beam undergoes as it travels through both media?

A. 11 dB
B. 6 dB
C. 15 dB
D. 3 dB

What does the 3.5 dB/cm represent?

A. the attenuation coefficient of the sound in the media
B. the attenuation of the sound in the media
C. the incident intensity of the ultrasound beam
D. all of the above

Which of the following best describes wave D and E?

A. in phase, different amplitudes
B. in phase, same amplitudes
C. in phase, different frequencies
D. out of phase, same amplitude

Impedance is important in _____ at boundaries.

A. reflections
B. refractions
C. scattering
D. transmission

If the frequency of sound is doubled, what happens to the wavelength?

A. wavelength is halved
B. wavelength is doubled
C. wavelength is quadrupled
D. wavelength remains unchanged

If the intensity remains the same while the power is doubled, what happens to the beam area?

A. doubled
B. quadrupled
C. halved
D. unchanged

The relative change in a sound beam’s intensity is measured in?

A. dB
B. watts/cm²
C. watts
D. pascals

A sound wave, with a intensity of 50 W/cm², strikes a boundary and is totally reflected. What is the intensity reflection coefficient?

A. 100%
B. 0%
C. 50 W/cm²
D. 25 W/cm²

Name the three components of attenuation.

A. absorption, reflection, and scattering
B. absorption, reflection, and impedance
C. absorption, reflection, and transmission
D. none of the above

What is 10^-6 x 10^-3?

A. 10^-9
B. 10^-3
C. 10^+3
D. 10^-6

Which of these media have the greatest attenuation and the fastest speed?

A. bone
B. tendon
C. lung
D. fat

Reflections from a smooth reflector are considered to be?

A. specular reflections
B.diffuse reflections
C. backscatter
D. rayleigh scattering

What does the 100 mW/cm² stand for?

A. the incident intensity of the ultrasound beam
B. the intensity emitted by the ultrasound beam
C. the incident intensity of the ultrasound unit
D. none of the above

Which of the following components is the dominant contributor to attenuation?

A. absorption
B. reflection
C. scattering
D. transmission

What is the relationship between US frequency and the attenuation coefficient in soft tissue?

A. in soft tissue, the attenuation coefficient in dB per centimeter is about 0.5 times the ultrasonic frequency in MHz.
B. in soft tissue, the attenuation coefficient in dB per centimeter is about 1.0 times the ultrasonic in MHz.
C. in soft tissue, the attenaution coefficient in dB per centimeter is about 3.5 times the ultrasonic in MHz.
D. none of the above

The intensity transmission coefficient of sound 99.9%. What percent of sound is reflected back to the transducer?

A. 0.1%
B. 0.01%
C. 100%
D. 0%

What is 10^-6 divided by 10^-3?

A. 10^-3
B. 10^-9
C. 10^-6
D. 10^+3

A hint that is commonly used when solving for Logarithms (Log). Count the ___?

A. count the zero
B. count the ones
C. false statement
D. none of the above

What are the units of relative amplitude?

A. dB
B. mm
C. Pa
D. Hz

In soft tissue, attenuation coefficient is directly related to ______.

A. frequency
B. the medium
C. the depth
D. oblique incidence

An ultrasound system operating at 100% power and the power setting is 0 dB. What would the power setting be when the system is operating at 10 % power?

A. -10 dB
B. -90 dB
C. 50 dB
D. -3 dB

Total attenuation in soft tissue is related to _____ and _____.

A. path length and frequency of sound
B. path length and speed of sound
C. frequency of sound and speed of sound
D. attenuation and impedance

If the final intensity is more than the initial intensity then the gain in dB must have been (+ or —)?

A. positive (+)
B. negative (—)
C. not enough information is provided to determine
D. unpredicted

What of the following best describes line D?

A. period
B. amplitude
C. frequency
D. none of the above

The power of a system is at 100% and this is 0 dB. What is the dB change when the system’s power is 50%?

A. -3 dB
B. 3 dB
C. -10 dB
D. -50 dB

Which of the following characteristics will create the fastest speed of sound?

A. low density, high stiffness
B. low density, low stiffness
C. high density, high stiffness
D. high density, low stiffness

A sound wave strikes a boundary at normal incidence. The impedance of the two media are identical. What percentage of the sound wave is refracted?

A. 0%
B. 50%
C. 75%
D. 100%

The initial intensity of wave is 2 mW/cm², and there is a change of 9 dB. What is the final intensity?

A. 16 mW/cm²
B. 10 mW/cm²
C. 6 mW/cm²
D. 2 mW/cm²

Which of the following terms best describes a reflection arising from a rough boundary?

A. non-specular
B. absolute
C. Rayleigh
D. smooth

A 10 MHz sound beam travels through two media. It attenuates 5 dB in medium A and 1 dB in medium B. What is the total attenuation that the sound beam undergoes as it travels through both media?

A. 6 dB
B. 10 dB
C. 16 dB
D. 15 dB

True or False. STPA is related to tissue heating?

Which of these media have the greatest attenuation and the slowest speed?

A. air
B. bone
C. tendon
D. fat

A sound wave strikes a boundary between two media with different impedances. The angle of incidence is non-orthogonal. Which of the following statements is most correct?

A. some of the sound may be reflected
B. all of the sound will be reflected
C. some of the sound will be reflected
D. some of the sound may be refracted

Attenuation in water is ________ than soft tissue.

A. much less than
B. less than
C. much greater than
D. greater than

Attenuation in bone is ______ than soft tissue.

A. greater than
B. less than
C. same as
D. unable to solve problem

What are the units for Attenuation?

A. decibels
B. decibels per centimeter
C. rayl
D. watts

Impedance is a characteristic of ________.

A. only in the medium
B. only the reflection
C. both the medium and reflection
D. only the depth

What happens at the boundary between media 3 and 4?

A. reflection may occur
B. reflection does not occur
C. refraction may occur
D. refraction does not occur

Rayleigh scattering is related to ___________.

A. frequency
B. depth
C. medium
D. none of the above