# Physics Quiz 1

 V = ? V = F X W Increase density = ? Increase density = decrease velocity Increase compressibility = ? Increase compressibility = decrease velocity Increase stiffness = ? Increase stiffness = increase velocity Pulse Repetition Frequency (PRF) The number of pulses emitted per second Unit: Hertz Typical range: 1-10KHz Pulse Repetition Period (PRP) The time from the beginning of one pulse to the beginning of the next Unit: Seconds Time of producing and receiving echo PRP = ? PRP = 1/PRF Pulse Duration (PD) The time during which the pulse actually occurs Unit: Seconds PD = ? PD = number of cycles X periodPD = number of cycles / Frequency Duty Factor (DF) The fraction of time the ultrasound pulse is being emitted during one pulse repetition period The DF of Continuous Wave is 1(100%) The DF of Pulse Wave is less than 1 DF = ? DF = Pulse Duration/ Pulse Repetition Period Spatial Pulse Length (SPL) The length or space over which an ultrasound pulse occurs Units : meter, mm Affects greatly of image resoultion-long SPL will interact with a tissue interface longer than a short SPL, which as blurred image Near Field Fresnel Zone Closer to the transducer Collimated beam Far Field Fraunhofer Zone Farther to the transducer Divergence of the beam Beam Shape Parameter Ultrasound frequency and transducer diameter affect the length of near field and divergence of far field Increase frequency and transducer diameter = increase near field length and decrease divergence of far field Increase Transducer diameter = Increase Transducer diameter = (frequency is constant) length of near field increase and decrease far field divergence Authorstephaniefu ID193972 Card SetPhysics Quiz 1 DescriptionPhysics Quiz 1 Updated2013-01-20T22:25:23Z Show Answers