# US Physics 121-150

 What term refers to regions of decreased particle density in sound beam? Rarefaction 10-³ equals: 1/1000 Which of the following represents the number 1234 in scientific notation? 1.234x10³ One MHz equals: 10(six) HZ Terms used to describe the strength of the sound beam include: Amplitude and intensity You are imaging with a 5 MHz linear array transducers. What sound parameter stays constant as the beam propagates through the tissue? Frequency, Intensity, Amplitude or Wavelength ( None of the above) Ultrasound propagation velocity depends on: Density and compressibility You notice that the image in the far field is less bright compared to the near field. This is due to: Sound attenuation Acoustic impedance: Equals density times the propagation speed What determines the speed of sound? Medium through which sound wave passes You will NOT see refraction in the sonographic image if: The sound beam is perpendicular to the interface The rate of sound attenuation is lowest in: Water When you perform a Doppler exam, the frequency of the transmitted signal is determined by: The frequency if the electrical signal applied to the transducer Power divided by the beam area is equal to the: Intensity Axial resolution is determined chiefly by: Pulse duration Choose two benefits of tissue harmonic imaging Grating lobe artifacts are reduced and lateral resolution is improved Acoustic impedance increases with which of the following: Increased tissue density and increased propagation speed When you adjust the pulse repetition frequency, you are changing: The number of pulses per second Which of the following would increase the spatial pulsed length? Increased number of cycles per pulse Doppler pulses used for diagnostic purposes are typically __ cycles long? 6-20 The time that it takes for one pulse to occur is known as the: Pulse duration The length of space over which one cycle occurs is known as the: Wavelength Bandwidth refers to: Range of frequencies in a pulse When sound strikes a specular reflector at an oblique angle, the angle of reflection is: Equal to but opposite the angle of incidence Which describes constructive interference? Sound waves are in phase and resulting amplitude is increased The dark area indicated by the arrow in this image is primarily due to: Increased attenuation Which sound beam frequency would exhibit the greatest intensity loss with increasing depth? 10 MHz Interference patterns of reflected waves causes: Acoustic speckle Attenuation of the sound beam is affected by: Absorption, Scattering and Reflection The transfer of acoustic energy into heat is termed: Absorption Authoramadaperedo ID224420 Card SetUS Physics 121-150 DescriptionPhysics Updated2013-06-20T05:48:58Z Show Answers