DMS Physics review Questions With Complete Solutions

Waves are classified according to whether or not they need a medium in which to propagate. A wave which needs a medium is called a(n) ______________________ wave, a wave which will propagate in a vacuum (the absence of a medium) is called a(n) ________________ wave correct answer: mechanical, electromagnetic What are the two classifications of mechanical waves? correct answer: Transverse and longitudinal Frequency has the units of: (select all that apply) A. Cycles/second B. Hz C. Hertz D. pulse width E. Amps F. 1/sec G. Volts correct answer: A, B, C, F Period has units of: (select all that apply) A. seconds B. Hz/time C. time D. mm correct answer: time or seconds For a 10 MHz wave, determine the period in A. Soft tissue B. Bone C. Air D. Water correct answer: All are 0.1 usec For a 10 MHz wave, determine the wavelength in soft tissue. correct answer: For a 10 MHz wave, determine the wavelength in air (assume c = 331 m/sec) correct answer: What determines the frequency? A. System and medium B. System and transducer C. Transducer D. Medium correct answer: system and transducer What determines the period? A. System and medium B. Medium C. System and transducer D. Transducer correct answer: System and transducer since the period is the reciprocal of the operating frequency, the system and transducer also determine the period Propagation velocity has units of: A. Distance/time B. Distance C. Time D. mm correct answer: Distance/time Since frequency is determined by the system and transducer, and the propagation velocity depends on the properties of the medium, and since f, Wavelength, and c are related, what must the wavelength depend on? A. System and transducer B. Frequency and propagation velocity C. Properties of medium D. Just frequency correct answer: Frequency and propagation velocity Two different ultrasound systems are used for the same view on the same patient. If the wavelength is different, then the ________________ must be different. A. (operating) frequency B. Frequency and propagation velocity C. Propagation velocity correct answer: Operating frequency Using the same frequency transducer on two different patients, if the wavelength is different than the ______________ must also be different. correct answer: Propagation velocity If both the frequency and propagation velocity double, the wavelength will: