SPI PRACTICE QUESTIONS complete and graded A+

SPI PRACTICE QUESTIONS complete and graded A+ Sound waves are: - longitudinal, mechanical The speed of sound in soft tissue is closest to: - 1,500 m/s The frequency closest to the lower limit of ultrasound is: - 15,000 Hz Which is not an acoustic variable? - intensity The effects of soft tissue on ultrasound are called: - acoustic propagation properties All of the following are true EXCEPT: - two waves with identical frequencies must interfere constructively Put in decreasing order: deci, deca, micro, centi - deca, deci, centi micro ______________ is the time to complete one cycle - period Which of the following sound waves is ultrasonic and least useful? - 30 KHz What is the frequency of a wave with a 1 msec period? - 1 KHz ______________ is the distance covered by one cycle - wavelength Which of the following is determined by the source and the medium? - range resolution Propagation speed = ______________ x wavelength - frequency As a result of ______________, the propagation speed increases - decreasing compressibility and density Put in decreasing order of propagation speed: gas, liquid, solid - solid, liquid, gas If the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the wavelength? - halved A sound wave's frequency is 10 MHz. The wave is traveling in soft tissue. What is its wavelength? - .15 mm If the frequency of an US wave is doubled, what happens to the period? - halved If the frequency of US is increased from 0.77MHz to 1.54MHz, what happens to the propagation speed? - remains the same The units of PRF are: - per minute The time from the beginning of a pulse until its end is ______________? - pulsed duration What happens to the speed of sound in a medium when the bulk modulus of the medium increases? - faster ___________ resolution is determined by SPL - radial or axial If a wave's amplitude is doubled, what happens to the power? - quadrupled Power of sound has units of: - watts If the intensity of a sound beam remains unchanged while the beam area is reduced in half, what has happened to the power? - halved Which of these intensities is the smallest? SATP, SPTP, SATA - SATA The duty factor for CW ultrasound is: - 1.0 What is the minimum value of the duty factor? - 0% What are the units of intensity? - watts/cm2 What happens to the speed of sound in a medium when the bulk modulus of the medium decreases? - slower