SPI EXAM QUESTIONS ALL SOLVED NEW VERIFIED UPDATE

SPI EXAM QUESTIONS ALL SOLVED NEW VERIFIED UPDATE What is a wave? - Answer- A cyclical Transfer of energy What kind of wave is a sound wave? - Answer- A mechanical longitudinal wave What are the types of interference? - Answer- Constructive, Destructive and Partial What is the Classification of Ultrasound? - Answer- 20 mhz-200Hz What is the classification of Diagnostic Ultrasound? - Answer- 12mhz-2mhz What is the propagation speed in soft tissue? - Answer- 1,540 mhz 1.54 m/msec 154,000 cm/sec A Longitudinal wave propagates by a series of ________ and ______ back and forth in the same direction as the wave propagates. - Answer- Compression and Rarefaction What are the acoustic variables of wave propagation? - Answer- Pressure, Density, Temperature and particle motion Equation for the frequency of the wave? - Answer- f=1/p Frequency and period are are determined by what? - Answer- The source If the Density increases what happens to the Bulk modulus and propagation velocity? - Answer- The Bulk Modulus increases and the Propagation increases If the density of the medium decreases what happens to the Bulk modulus and propagation velocity? - Answer- The bulk modulus decreases and the propagation decreases Stiffness is the same as what? - Answer- Bulk Modulus Stiffness and compressibility are __________ related - Answer- Inversely What is the equation for the wavelength? - Answer- wavelength= c/f What is the amplitude? - Answer- Maximum variation of a variable from its mean What are the equations for the amplitude? - Answer- Max-Min Mean-Min Max-min/2 Power is proportional to the amplitude _______. - Answer- Amplitude Squared What is the definition of intensity? - Answer- I=Power/Area The top Diagnostic frequencies are limited by what? - Answer- Penetration Low frequencies a limited by what? - Answer- Resolution 3 dB factor of - Answer- 2 10dB factor of - Answer- 10 What is attenuation? - Answer- The conversion of sound into heat What are the factors of attenuation? - Answer- Absorption, Reflection and Refraction What are the key factors of Absorption? - Answer- It is the dominant form of attenuation and it increases exponentially w/ increasing frequency. What are the two types of reflection? - Answer- Acoustic and geometric what are the kinds of geometric reflectors? - Answer- - Specular reflectors -Scatterers -Rayleigh scattering What causes refraction? - Answer- -Different propagation speeds -Obliques angle of incidence What causes lateral Displacement? - Answer- refraction, the machine is not aware that refraction occurs. What does total internal reflection caused by? - Answer- Critical angle What is the attenuation rate in soft tissue? - Answer- 0.5 What is the Attenuation coefficient of soft tissue? - Answer- 1/2fo What is the Equation for conservation of energy? - Answer- Reflection % + Transmission % = 100% Describe anechoic - Answer- No echogencity (Dark) Describe Hypoechoic - Answer- Low echogenicity (Dark) Describe Hyperechoic - Answer- High echogenicity (Bright) Describe Calcified - Answer- Strongly echogenic, usually w/ acoustic shadowing Type of reflection that occurs at an interface depends on what? - Answer- The size of the wave length compared to the size of the surface geometry. Acoustic impedance is measured in what? - Answer- Rayls How is pulsed wave created? - Answer- The pulser is turned on and off what is the Range resolution equation? - Answer- SPL/2 Explain the wave parameter Period - Answer- The *time* it takes for one cycle to occur, p=1/f, measured in seconds and is determined by the source. Explain the wave parameter Pulse Duration - Answer- The time for one pulse to occur, PD=P #Cycles, measured in seconds and is determined by the source.