Edelmen's SPI Exam Review, Questions and answers. 100% Accurate. Rated A Sound waves are:

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Edelmen's SPI Exam Review, Questions and answers. 100% Accurate. Rated A Sound waves are: a) electric b) mechanical, transverse c) spectral d) longitudinal, mechanical - ✔✔D The speed ... of sound of ultrasound in soft tissue is closest to: a) 1,540 km/sec b) 1.54 km/sec c) 1,500 m/s d) 1,540 mm/sec - ✔✔C Which is not an acoustic variable? a) density b) pressure c) distance d) intensity - ✔✔D The effects of soft tissue on ultrasound are called: a) acoustic proliferation properties b) dynamic effects c) acoustic propagation properties d) biological effects - ✔✔C All of the following are true EXCEPT: a) two waves with identical frequencies must interfere constructively. b) constructive interference is associated with waves that are in-phase. c) out-of-phase waves interfere destructively. d) waves of different frequencies may exhibit both constructive and destructive interference at different times. - ✔✔A Put in decreasing order: a) deca b) deci c) micro d) centi - ✔✔abdc ______ is the time to complete one cycle a) pulse duration b) pulse period c) period d) duration period - ✔✔C Which of the following sound waves is ultrasonic and least useful in diagnostic imaging? a) 30 KHz b) 8 Mhz c) 8,000 Hz d) 3,000 Hz e) 15 Hz - ✔✔A ______ is the distance covered by one cycle. a) pulse length b) wavelength c) cycle distance d) cycle duration - ✔✔B Which of the following is determined by the source and the medium? a) frequency b) period c) propagation speed d) range resolution - ✔✔D Propagation speed = _______ x wavelength a) pulse duration b) period c) # of cycles in the pulse d) frequency - ✔✔D 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 Put in decreasing order of propagation speed. a) gas b) liquid c) solid - ✔✔c b a If the frequency of an ultrasound wave is doubled, what happens to the period? a) doubles b) halved c) remains the same d) 4x greater - ✔✔B The units of pulse repetition frequency are: a) per minute b) microseconds c) mm/microseconds d) MHz - ✔✔A The time from the beginning of the pulse to the end of that pulse is _______? a) period b) pulse duration c) pulse length d) PRF - ✔✔B What happens to the speed of sound in a medium when the bulk modulus increases? a) faster b) slower c) unchanged - ✔✔A _________ resolution is determined by the spatial pulse length a) radial b) image c) axial d) angular - ✔✔A or C If the wave's amplitude is doubles, what happens to the power? a) nothing b) halved c) doubled d) quadrupled - ✔✔D If the level of acoustic variable ranges from 55-105, what is the amplitude? a) 105 b) 50 c) 25 d) 55 - ✔✔25 Power of sound has units of: a) dB b) dB/cm c) watts d) watts/cm^2 - ✔✔C If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power? a) quadrupled b) doubled c) halved d) unchanged - ✔✔C Which of these intensities is the smallest? a) SATP b) SPTP c) SATA - ✔✔C The duty factor for CW ultrasound is a) 10.0 b) 1% c) 1.0 d) 0.0% - ✔✔C What is the minimum value of the duty factor? a) 10.0 b) 1% c) 1.0 d) 0.0% - ✔✔D What are the units of intensity? a) watts b) dB c) watts/cm^2 d) dB - ✔✔C What happens to the speed of sound in a medium when the bulk modulus of the medium decreases? a) faster b) slower d) unchanged - ✔✔B The units of attenuation are ___ : this is a ___ scale A) mm/cm ; parametric B) dB/m ; multiplicative C) none ; relative D) dB ; logarithmic - ✔✔D Sound Intensity decreased by 75% is how decibels of attenuation? a) 6dB b) 9 dB c) 5 dB d) 10 dB - ✔✔A If a 5 MHz wave is traveling in the tissues listed below, which will have the longest wavelength? a) fat b) air c) muscle d) bone - ✔✔D If a 5 MHz wave is traveling in the tissues listed below, which will have the shortest wavelength? a) fat b) air c) muscle d) bone - ✔✔B The rayl is the unit of.... a) intensity b) reflectance c) density d) impedance - ✔✔D Impedance is the _______ of _______ and ________. a) product, propagation speed and density b) sum, stiffness and density c) quotient, stiffness and propagation speed. d) difference, attenuation and density - ✔✔A What the three attenuation components? - ✔✔scattering, reflection, and absorption In soft tissue, the approximate attenuation coefficient in dB/cm is equal to 1/2 of ______ in ______. - ✔✔Frequency, in MHz As the impedance of two media become vastly different, the.... a) reflection increases b) transmission increases c) refraction increases d) absorption increases - ✔✔A The angle between the ultrasound pulse and the boundary between two media is 90deg. What is this called? a) direct incidence b) oblique incidence c) indirect incidence d) orthogonal incidence - ✔✔D The angle between the ultrasound pulse and the boundary between two media is 56deg. What is this called? a) direct incidence b) oblique incidence c) indirect incidence d) orthogonal incidence - ✔✔B Refraction only occurs if there are: a) normal incidence & different impedances b) indirect intensity & different propagation speeds c) oblique incidence and different propagation speeds d) oblique frequency & identical impedences - ✔✔C *With normal incidence, what factors affect refraction of US? A) propagation speeds B) frequencies C) attenuation coefficients D) none of the above - ✔✔D ________ is a redirection of an ultrasound bean in many directions as a result of a rough boundary between two media: a) refraction b) Rayleigh Scattering c) scattering d) reflection - ✔✔C Which is most likely to create Rayleigh Scattering? a) Red Blood Cells b) muscle c) scattering d) bone - ✔✔A True or False: With normal incidence, the angle is 180deg. - ✔✔False Which of the following conditions is axial resolution improved? a) decreases spatial pulse length b) decreased pulse amplitude c) decreased imaging depth d) decreased pixel size e) decreased beam diamete - ✔✔A [Show More]

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