spi review physics
14. How many hertz is 3 MHz a. 3,000,000 b. 3000 c. 333 d. 0.003
a
A 3 dB gain would indicate an increase in intensity by: a. 2 times b. 4 times c. 8 times d. 10 times
a
A decibel (dB) describes the: a. Ratio of two sound intensities b. Sum of two sound intensities c. Amount of scattering d. Velocity of the sound wave
a
A transducer with which frequency would have the thickest element(s)? a. 2 MHz b. 3.5 MHz c. 5 MHz d. 7.5 MHz
a
ALARA stands for: a. As low as reasonably achievable b. As long as reasonably acceptable c. As little as reasonably allowable d. As long as reasonably achievable
a
All of the following are true EXCEPT: a. Two waves with identical frequencies must interfere constructively b. Constructive inferference is associated with waves that are in-phase c. Out-of-phase waves inferfere destructively d. Waves of different frequencies may exhibit both constructive and destructive interference at different times
a
An increase in pulse repetition frequency would lead to: a. An increase in duty factor b. An increase in pulse duration c. An increase in the number of cycles d. A decrease in resolution
a
Areas of high pressure and density are referred to as: a. Compressions b. Rarefactions c. Condensations d. Rarefractions
a
Arrange the following media in terms of propagation speed, from lowest to highest. a. Air, fat, muscle, bone b. Bone, fat, air, muscle c. Bone, muscle, fat, air d. Muscle, air, fat, bone
a
Attenuation denotes: a. Progressive weakening of the sound beam as it travels b. Density of tissue and the speed of sound in the tissues c. The redirection of the ultrasound back to the transducer d. Bending of the transmitted wave after crossing an interface
a
Density is typically measured in: a. Kilograms per centimeter cubed b. Millimeters c. watts per centimeter squared d. pascals
a
Diffraction refers to: a. Spreading out of the ultrasound beam b. Conversion of sound to heat c. Redirection of a portion of the sound from a boundary beam d. Bending of the sound beam crossing a boundary
a
If the gain of an amplifier is 18 dB, what is the new gain if the power is reduced by half? a. 15 dB b. 9 dB c. 36 dB d. 0.5 dB
a
Micro denotes: a. Millionth b. Hundredth c. Million d. Billionth
a
Put in decreasing order a. Deca, Deci, Micro, Centi b. deci, deca, mirco, centi c. micro, centi, deca, deci d. micro, centri, deci, deca
a
Rayleigh scattering is an example of: a. A reflector whose size is smaller than the wavelength b. A reflector whose size is significantly larger than the wavelength c. A specular reflection d. A type of side lobe artifact
a
Specular reflections: a. Occur when the interface is larger than the wavelength b. Occur when the interface is smaller than the wavelength c. Arise from interfaces smaller than 3 mm d. Are not dependent on the angle of incidence
a
The acoustic impedance of the transducer's matching layer: a. Is chosen to improve transmission into the body b. Is chosen to have increased internal reflections c. Determines the frequency d. None of the above
a
The attenuation coefficient in soft tissue is equal to: a. One half of the operating frequency b. Double the operating frequency c. Frequency times path length d. The total decibels
a
The typical value for attenuation coefficient for 6 MHz ultrasound in soft tissue is: a. 3 dB/cm b. 1 dB/cm/Hz c. 3 dB/cm2 d. 2 dB
a
The unit for wavelength is: a. Millimeters b. Hertz c. Microseconds d. Milliliters
a
The wavelength in a material having a propogation speed of 1.4 mm/s emplying a transducer frequency of 5.0 mhz is: a. 0.3 mm b. 0.3 cm c. 0.6 mm d. 3.0 mm
a
What component of the ultrasound system contains the digital-to- analog converter? a. Scan converter b. Pulser c. Receiver d. Display
a
What happens to intensity if the amplitude of a signal is halved? a. Quartered b. Quadrupled c. Halved d. No change
a
What is the reflected intensity from a boundary between two materials if the incident intensity is 1 mW/cm2 and the impedances are 25 and 75? a. 0.25 mW/cm2 b. 0.33 mW/cm2 c. 0.50 mW/cm2 d. 1.0 mW/cm2
a
What portion of the ultrasound system drives the transducer? a. Pulser b. Receiver c. Scan converter d. TGC controls
a
Which of the following are most commonly used in ultrasound transducers? a. Lead zirconate titanate b. Barium sulfate c. Epoxy loaded with tungsten d. Quartz
a
Which of the following is an effect of focusing? a. Improved lateral resolution b. Improved axial resolution c. Increased beam divergence d. Higher frequency
a
Which of the following is described as the ability of an object to resist compression and relates to the hardness of a medium? a. Stiffness b. Density c. Pressure d. Inertia
a
Which of the following transducers fires the elements in groups? a. Linear sequenced array b. Phased array c. Mechanical sector d. Linear phased array
a
All of the following are true of stiffness except :a. It is defined as the ability of an object to resist compression b. Stiffness and propagation speed are indirectly associated c. Increasing stiffness increases propagation speed d. Stiffness may also be referred to as elasticity
b
An ultrasound transducer converts :a. Electrical energy into light and heat b. Electrical energy into mechanical energy c. Mechanical energy into radiation d. Sound into ultrasound
b
Continuous-wave Doppler has a duty factor of: a. <1% b. 100% c. >100% d. 50%
b
How much bigger is a thousand than ten? a. 10 times b. 100 times c. 1000 times d. 500 times
b
If medium 2 impedance is equal to medium 1 impedance: a. 100% of the intensity will be reflected b. 100% of the intensity will be transmitted c. The reflection and transmission coefficients will be equal d. The answer cannot be determined without values given
b
Ignoring the effects of attenuation, the intensity of the ultrasound beam is usually greater at the focal zone because of: a. Decreased attenuation b. The smaller beam diameter c. Diffraction effects d. A shorter duty factor
b
Pressure is typically expressed in: a. Frequency b. Pascals c. Decibels d. Kilograms per centimeter cubed
b
The echoes are stored before final display by the: a. Receiver b. Scan converter c. Demodulator d. Transducer
b
The intensity transmission coefficient is equal to: a. 1 intensity reflection coefficient b. 1 intensity reflection coefficient c. The square of the angle of transmission d. (Intensity transmission coefficient)/2
b
The piezoelectric effect can best be described as: a. Density of tissue and the speed of sound in the tissues b. Mechanical deformation that results from a high voltage applied to the face of the crystal that in turn generates a pressure wave c. Having a damaging effect on crystal due to high voltage d. The decrease in intensity that results from the application of a damping material
b
The range equation explains: a. Side lobes b. Distance to reflector c. Attenuation d. Calibration
b
The region where the sound beam is the smallest is referred to as the: a. Fresnel spot b. Focus c. Near field d. Far field
b
The speed of sound in soft tissue is: a. 1.54 mm/s b. 1540 m/s c. 1540 km/s d. 1.54 m/s
b
The thinner the piezoelectric element, a. The lower the frequency b. The higher the frequency c. The higher the amplitude d. The lower the amplitude
b
The typical range of frequency for diagnostic ultrasound imaging is: a. 20 to 20,000 Hz b. 1 to 20 MHz c. 10 to 20 MHz d. 12 to 100 MHz
b
Ultrasound attenuates an average of ___________________dB/cm of travel for each megahertz of frequency. a. 1 b. 0.7 c. 0.33 d. 0.25
b
What is the definition of the beam uniformity ratio? a. The spatial intensity divided by the spatial peak intensity b. The spatial peak intensity divided by the spatial average intensity c. The temporal average intensity divided by the spatial average intensity d. The temporal peak intensity divided by the spatial peak intensity
b
What is the total attenuation of a 3.5-MHz pulse after passing through 2 cm of soft tissue? a. 7 dB b. 3.5 dB c. 17 dB d. 1.75 dB
b
Which of the following is true? a. SPTA is always equal to or greater than SPTP b. SPTP is always equal to or greater than SPTA c. SATA is always equal to or greater than SATP d. SPTA is equal to or greater than SPTP
b
Which of the following would have the highest propagation speed? a. Air b. Bone c. Soft tissue d. Water
b
Within the same medium using the same transducer, decreasing the _______________ decreases the beam diameter in the _______________. a. Frequency, far zone b. Wavelength, far zone c. Frequency, near zone d. Intensity, far zone
b
_____ is the distance covered by one cycle. a. Pulse length b. Wavelength c. Cycle distance d. Cycle duration
b
what is the intensity reflection coefficient if medium 1 has an impedance of 1 MR and medium 2 has an impedance of 4 MR a. .37 b. 36% c. 37% d. 3.6
b
what is the reciprocal of 20? a. 0.20 b. 1/20 c. 20 d. 20/1
b
A sound beam encounters an interface at a 90 angle. If the speed of sound in the first tissue is 1540 m/s and the speed of sound in the second tissue is 1450 m/s, which of the following numbers most closely approximates the angle of beam transmission? a. <90 b. 90 c. >90 d. Need the impedance to compute angle of transmission
c
Acoustic impedance is defined as the product of: a. The mismatch between two interfaces b. A change in velocity at oblique incidence c. The speed of sound in tissue and density of the tissue d. The wavelength and frequency
c
Arrange the following media in correct order from the lowest attenuation to highest .a. Air, fat, muscle, bone b. Muscle, fat, air, bone c. Fat, muscle, bone, air d. Muscle, air, fat, bone
c
As a result of _____ the propagation speed increases. a. increasing stiffness and increasing density b. Increasing stiffness and increasing elasticity c. Decreasing compressibility and decreasing density d. Decreasing stiffness and decreasing density
c
As imaging depth increases, the pulse repetition frequency must: a. Not change b. Increase c. Decrease d. Pulse repetition frequency does not relate to imaging depth
c
Bandwidth is: a. A source of artifacts b. A potential shade of gray c. The range of frequencies produced by the transducer d. Undesirable interference or noise
c
How many kilometers are in 3000 meters? A. 1/300 B. 1/3 c. 3 D. 300 E. 3000
c
If the amount of damping decreases, the bandwidth: a. Stays the same b. Increases c. Decreases d. Damping and bandwidth are unrelated
c
If the amplitude of a wave is increased threefold, the power will: a. Decrease threefold b. Increase threefold c. Increase ninefold d. Increase sixfold
c
If the frequency doubles, what happens to the wavelength? a. Increases fourfold b. Increases twofold c. Decreases by one half d. Frequency has no relationship to wavelength
c
If the intensity transmission coefficient is 0.74, the intensity reflection coefficient will be :a. 1.06 b. 6.00 c. 0.26 d. 0.04
c
Spatial pulse length can be calculated by a. Multiplying the number of cycles times the frequency b. Dividing the period by the frequency c. Multiplying the number of cycles times the wavelength d. Dividing the number of cycles by the wavelength
c
The attenuation coefficient of sound in soft tissue can be defined by which of the following equations? a. One half the frequency times the path length b. Frequency/6 c. Frequency/2 d. Frequency 2
c
The correct equation for Snell's law is: a. R (Z2 Z1)2/(Z2 Z1)2 b. Z pc c. sin ut (C2/C1) sin ui d. Fd 2fvcos u/c
c
The effects of soft tissue on US are called: a. Acoustic proliferation properties b. Dynamic effects c. Acoustic propagation properties d. Biologic effects
c
The method for sterilizing transducers is: a. Heat sterilization b. Steam c. Cold sterilization d. Autoclave
c
The spatial pulse length is defined as the product of the _____________ and the number of _____________ in a pulse? a. Cycles, frequency b. Frequency, velocity c. Wavelength, cycles d. Frequency, wavelength
c
The speed of US in soft tissue is closest to a. 1.540 km/sec b. 1.54 km/msec c. 1.500 m/s d. 1.540 mm/sec
c
The type of transducer that utilizes concentric rings is called: a. Sequential array b. Phased array c. Annular array d. Spatial array
c
The unit for impedance is: a. dB b. mW/cm2 c. Rayls d. No units
c
What is the frequency of a wave with 1 msec period? a. 10.00 Hz b. 1.00 kHz c. 1 kHz d. 1 MHz
c
What is the name of the control that compensates for attenuation related to path length? a. Near gain b. Far gain c. TGC d. Reject
c
What must be known in order to calculate distance to a reflector? a. Attenuation, propagation speed, density b. Attenuation, impedance c. Travel time, propagation speed d. Density, propagation speed
c
Which of the following is best defined as the ability to discriminate between two closely spaced reflectors? a. Definition b. Range accuracy c. Spatial resolution d. Amplification
c
Which of the following is described best as a transducer that has multiple elements in a curved shape? a. Annular array b. Mechanical sector c. Curvilinear d. Linear array
c
Which of the following relates bandwidth to operating frequency? a. Near zone b. Piezoelectric crystal c. Quality factor d. Far zone
c
With phased array transducers, the transmitted sound beam is steered by: a. Mechanically sweeping the piezoelectric elements b. Mechanically rotating the piezoelectric elements c. Varying the timing of pulses to the individual piezoelectric elements d. Varying the frequency of pulses to the individual piezoelectric elements
c
______ is the time to complete on cycle a. Pulse duration b. Pulse period c. Period d. duration period
c
the frequency ranges for ultrasound are a. <20 Hz b. 20-20,000 hz c. >20 khz d. >2000 hz
c
12. What is the reciprocal of 100? A. 0.1 B. 100 c. 0.2 d. 0.01 e. 1/50
d
A wave's initial intensity is 2 mW/cm2. There is an increase of 10 dB. What is the final intensity? a. 4 mW/cm3 b. 8 mW/cm2 c. 12 mW/cm2 d. 20 mW/cm2
d
All of the following are measures of length except A. mile B. inch. c. mm d. sec
d
As a sound wave travels through the human body, the intensity of the sound wave decreases as a result of :a. Attenuation b. Absorption c. Scattering d. All of the above
d
Enhancement is caused by: a. Strongly reflecting structures b. Propagation speed errors c. Snell's law d. Weakly attenuating structures
d
How many bits per pixel can be displayed with 4 bits of memory? a. 2 b. 4 c. 8 d. 16
d
How many centimeters are in 3 meters? A. 1/300 B. 1/3 c. 3 d. 300 E. 3000
d
How many different shades of gray can the human eye discern at one time? a. 16 b. 32 c. 64 d. 100
d
Most current ultrasound systems have _______ shades of gray available. a. 4 b. 32 c. 64 d. 256
d
Propagation speed = _______ x wavelength a. Pulse duration b. Period c. Number of cycles in the pulse d. Frequency
d
Sound waves are a. electric b. mechanical c. spectral d. longitudinal mechanical
d
The frequency closest to the lower limit of US is a. 19.000 kHz b. 10.000 MHz c. 20.000 msec d. 15.000 Hz
d
The layer of material within the transducer which has an intermediate impedance between the transducer element and human tissue is known as the: a. Filler medium b. Damping medium c. Acoustic medium d. Matching layer
d
The near zone length is determined by: a. Number of focal zones b. Frame rate c. Pulse repetition frequency d. Transducer frequency
d
What is the reciprocal of 1/8? A. 80 b. 10 c. 1 d. 8 e. 72
d
Which of the following describes the amount of refraction that occurs at an interface? a. Bernoulli's law b. Poiseuille's law c. Law of reflection d. Snell's law
d
Which of the following has the lowest intensity? a. SPTP b. SATP c. SPTA d. SATA
d
Which of the following is described as the distance over which one cycle occurs? a. Pulse duration b. Duty factor c. Period d. Wavelength
d
Which of the following is determined by the source and the medium? a. Frequency b. Period c. Propagation speed d. Range resolution
d
Which of the following would be used to describe the percentage of time that sound is on? a. Intensity b. Amplitude c. SPTA d. Duty factor
d
Which of the following would have the lowest propagation speed? a. Water b. Soft tissue c. Bone d. Lung tissue
d
what is not an acoustic variable a. Density b. Pressure c. Distance d. Intensity
d
Axial resolution is improved by (A) focusing (B) acoustic mirrors (C) acoustic lens (D) beam diameter (E) damping
e
How many milliliters are in 8 liters? A. 1/8 B. 8 C. 80 d. 800 e. 8000
e
The spatial pulse length (A) determines the speed of ultrasound in tissue (B) usually increases with higher frequency (C) is improved with rectification (D) determines lateral resolution (E) usually decreases with higher frequency
e
