SPI Practice Test Questions and answers. 100% Accurate. Rated A

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SPI Practice Test Questions and answers. 100% Accurate. Rated A Which of the following do the source and the medium determine? a. duty factor b. frequency c. propagation speed d. axial resoluti... on - ✔✔d. Axial resolution is affected by all of the following EXCEPT a. frequency b. damping c. spatial pulse length d. focusing - ✔✔d. Damping in a transducer a. reduces the number of cycles in a pulse and increases the quality factor b. increases the number of cycles in a pulse and increases penetration c. causes poor axial and lateral resolution d. reduces the duty factor and increases the range of transmitted frequencies - ✔✔d. Far zone beam divergence can be reduced on a single-element transducer by using a. a transducer with a smaller element diameter b. a higher frequency transducer c. a lower frequency transducer or a smaller element diameter d. adjustable focusing - ✔✔b. The area between the face of an unfocused single-element transducer and the point where the beam starts to diverge is the a. Fraunhofer zone b. refraction zone c. focal zone d. near zone - ✔✔d. Assuming a fixed frequency, what happens if the diameter of an unfocused transducer is increased? a. the far zone divergence increases b. the penetration decreases c. the length of the near zone increases d. the length of the near zone decreases - ✔✔c. Which of the following does NOT affect lateral resolution? a. focusing b. element diameter c. frequency d. bandwidth - ✔✔d. Higher frequency transducers provide a. improved lateral resolution b. smaller Doppler shifts c. improved axial resolution and reduced attenuation d. increased penetration - ✔✔a. Ultrasound waves that are traveling through a medium consist of a. electromagnetic and radio frequencies b. compressions and refractions c. electromagnetic and ionizing frequencies d. compressions and rarefactions - ✔✔d. What is the difference between audible sound and ultrasound? a. audible sound waves can travel through a vacuum b. audible sound has a higher frequency c. ultrasound has a higher frequency d. ultrasound waves are ionizing - ✔✔c. A decrease in the thickness of a piezoelectric element will result in a. a greater pulse duration b. an increase in the propagation speed c. a decrease in the quality factor if the bandwidth decreases d. an increase in the frequency of the transducer - ✔✔d. The resonant frequency of a pulsed-wave ultrasound transducer is dependent on a. damping b. the backing material c. the thickness of the piezoelectric element and the speed of sound through the piezoelectric element d. the amplitude of the voltage applied to the piezoelectric element - ✔✔c. The image is brighter at the level of the focal zone. Which of the following controls is best to correct this? a. overall gain b. TGC c. acoustic power d. PRF - ✔✔b. If the frequency is doubled, a. the duty factor will increase b. the period will double c. the wavelength will double d. the wavelength will be one-half - ✔✔d. The typical range of pulse repetition frequencies in a pulse-echo ultrasound system is a. 2,000 Hz to 20,000 Hz b. 20 MHz to 200 MHz c. 20,000 Hz to 200,000 Hz d. 1,000 Hz to 2,000 Hz - ✔✔d. If the number of cycles in a pulse is reduced, a. the pulse repetition frequency is automatically reduced b. the spatial pulse length increases c. the pulse duration is reduced which results in a lower duty factor d. the bandwidth is decreased and the quality factor is increased - ✔✔c. The minimum reflector separation required to produce separate echoes is a. the spatial resolution of the ultrasound system b. the temporal resolution c. the attenuation coefficient d. the total attentuation - ✔✔a. As the frequency of sound increases, a. the amount of scatter is increased b. the attenuation decreases c. the amount of scatter decreases d. the penetration increases - ✔✔a. Which of the following transducers provides the maximum penetration? a. 10.0 MHz b. 7.5 MHz c. 2.25 MHz d. 3.5 MHz - ✔✔c. The average attenuation of ultrasound energy in the patient is approximately a. 2.0 dB per cm per MHz b. 10.0 dB per cm per MHz c. 5. dB per cm per MHz d. 0.7 dB per cm per MHz - ✔✔d. If sound from a 3 MHz transducer has 3 dB of attenuation after traveling through 2 cm of tissue, what is the amount of attenuation of sound from a 5 MHz transducer after traveling through 1 cm of the same tissue? a. 5 dB b. 1 dB c. 2 dB d. 2.5 dB - ✔✔d. The half-value layer or the half-intensity-depth a. is the depth where the intensity is 50% of the originally transmitted intensity b. increases as the frequency of the transmitter increases c. is the range of frequencies contained in an ultrasound pulse d. is the attenuation coefficient in tissue - ✔✔a. The speed of ultrasound in soft tissue is closest to a. 1.54 mm/sec b. 1540 km/sec c. 1540 mm/sec d. 1540 m/s - ✔✔d. Ultrasound energy is traveling through the same medium. If the frequency is doubled, the propagation speed is a. quartered b. doubled c. halved d. unchanged - ✔✔d. The reason most ultrasound systems are calibrated at 1540 meters per second is because a. 1540 meters per second is the average speed of sound encountered in the patient b. 1540 meters per second is the maximum speed of sound encountered in a patient c. 1540 meters per second is the speed of sound in muscle d. 1540 meters per second is the maximum speed of sound in a patient - ✔✔a. The propagation speed is highest in a. bone b. tissue c. fat d. muscle - ✔✔a. The redirection of sound energy in many directions as a result of a rough boundary between two media is a. shadowing b. specular reflection c. through-transmission d. scattering - ✔✔d. The density is the same in materials A and B, but the speed of sound in material B is 10% greater than the speed of sound in material A. a. The acoustic impedance in B is 10% greater than the acoustic impedance in A b. The sound velocity in A is 10% higher than the propagation speed in B c. The acoustic impedance in A is equal to the acoustic impedance in B d. The acoustic impedance in A is 10% higher than the acoustic impedance in B - ✔✔a. Matching layers in a transducer a. improve axial resolution b. provide damping c. determine the operating frequency d. provide greater efficiency of sound transmission from the transducer to the patient - ✔✔d. The acoustic impedance of a matching layer in a transducer should have a value a. between the acoustic impedance of the piezoelectric element and the acoustic impedance of tissue b. lower than the acoustic impedance of tissue c. greater than the acoustic impedance of the piezoelectric element d. equal to the acoustic impedance of the piezoelectric element - ✔✔a. The prefix micro- represents the mathematical value a. 10 to the 6th power b. 10 to the negative 6th power c. 10 to the third power d. 10 to the negative third power - ✔✔b. The representation for volume is a. m b. cm c. cm squared d. cm cubed - ✔✔d. If the amplitude is decreased by 50%, what is the corresponding change in power? a. -6 dB b. 3 dB c. -3 dB d. 0 dB - ✔✔a. If the relative output power of an ultrasound instrument is calibrated in decibels and the operator increases the output by 20 dB. the beam intensity is increased by a. twenty times b. fiver percent c. one hundred times d. one million times - ✔✔c. A decrease in power or intensity by a factor of 2 represents a change of a. -3 dB b. -50 dB c. -6 dB d. 3 B - ✔✔a. The Power control on an ultrasound system is set at maximum. The display indicates PWR= 0 dB. If this Power control is used to reduce the intensity by one-half, the display will indicate PWR= a. 2 dB b. 0 dB c. -3 dB d. -6 dB - ✔✔c. Sound power is measured in units o [Show More]

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