Sonography Canada CORE (Physics) Questions With Complete Solutions

form of energy to another form of energy what does an ultrasound transducer do? correct answer: converts electropotential energy into mechanical and mechanical energy into electropotential energy what is the curie point? correct answer: if a crystal is heated beyond the curie point (360 degrees for PZT) the crystal can lose piezoelectric effects what material is traditionally used for ultrasound trasnducers? correct answer: Lead ziconate titanate (PZT) what are modern transducers made out of? correct answer: composite materials to achieve greater conversion efficiency with less of an acoustic impedance mismatch Near zone (fresnel) correct answer: the area between the face of the transducer and the beam focus Far zone (Fraunhofer) correct answer: Region past the focus Focus correct answer: Where the beam reaches its minimum diameter Focal region correct answer: Region over whch the beam is most tightly focused Detail resolution correct answer: Ability to distinguish between two objects in any of the three dimensions (Axial,lateral, elevational) Operating frequency correct answer: Center frequency of the transmit bandwidth what are four methods of focusing the ultrasound beam correct answer: 1)Lenses