SPI PRACTICE QUESTIONS AND ANSWERS

Sound waves are: - Answer- longitudinal, mechanical The speed of sound in soft tissue is closest to: - Answer- 1,500 m/s The frequency closest to the lower limit of ultrasound is: - Answer- 15,000 Hz Which is not an acoustic variable? - Answer- intensity The effects of soft tissue on ultrasound are called: - Answer- acoustic propagation properties All of the following are true EXCEPT: - Answer- two waves with identical frequencies must interfere constructively Put in decreasing order: deci, deca, micro, centi - Answer- deca, deci, centi micro ______________ is the time to complete one cycle - Answer- period Which of the following sound waves is ultrasonic and least useful? - Answer- 30 KHz What is the frequency of a wave with a 1 msec period? - Answer- 1 KHz ______________ is the distance covered by one cycle - Answer- wavelength Which of the following is determined by the source and the medium? - Answer- range resolution Propagation speed = ______________ x wavelength - Answer- frequency As a result of ______________, the propagation speed increases - Answer- decreasing compressibility and density Put in decreasing order of propagation speed: gas, liquid, solid - Answer- solid, liquid, gas If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength? - Answer- halved A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength? - Answer- .15 mm If the frequency of an US wave is doubled, what happens to the period? - Answer- halved