ARDMS SPI LATEST ACTUAL EXAM

ARDMS – SPI LATEST ACTUAL EXAM

ANSWERS| AGRADE

what type of wave is a sound wave? Correct Answer longitudinal, mechanical

molecules of the medium vibrate at 90 degrees to the direction of the traveling wave Correct Answer transverse wave

what is the range of audible sound? Correct Answer 20 Hz to 20 kHz

portion of a cycle where the molecules are pushed closer together Correct Answer compression

portion of a cycle where the molecules spread farther apart Correct Answer rarefaction

what are the three primary acoustic variables? Correct Answer pressure, density, particle motion

the time it takes for one cycle to occur Correct Answer period

the number of cycles per second Correct Answer frequency

relationship between period and frequency Correct Answer inverse

the speed at which sound travels through a medium Correct Answer propagation speed (c)

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relationship between stiffness and propagation speed Correct Answer direct

"c" of soft tissue Correct Answer 1540 m/s or 1.54 mm/usec

relationship between density, compressibility & elasticity to propagation speed Correct Answer inverse

length of a single cycle Correct Answer wavelength

wavelength formula Correct Answer propagation speed/frequency

max or min deviation of an acoustic variable from the average value of that variable Correct Answer amplitude

units of pressure amplitude Correct Answer pascals (Pa)

the rate at which work is performed Correct Answer power

how are power and amplitude proportioned? Correct Answer power = amplitude squared

intensity formula Correct Answer power/area (w/cm^2)

resistance to the propagation of sound through a medium Correct Answer impedance (z)

units for impedance Correct Answer rayls

what causes a strong reflection? Correct Answer 90 degree incidence and strong impedance mismatch

impedance formula Correct Answer z = density (p) x propagation speed (c)

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sound waves are sent into the body and the returning wave is timed to determine the reflectors distance from the transducer Correct Answer pulse-echo technique

most common element material Correct Answer lead zirconate titanate (PZT)

pressure is created when voltage is applied to a material and electricity is created when pressure is applied to the material Correct Answer piezoelectric principle

number of pulses produced in 1 second Correct Answer pulse repetition frequency (kHz)

relationship between frequency and PRF Correct Answer none

how are depth and PRF related Correct Answer inverse

the time from the start of one pulse to the start of the next pulse Correct Answer pulse repetition period

relationship between PRP and PRF Correct Answer inverse

relationship between PRP and depth Correct Answer direct

time during which the sound is being transmitted Correct Answer pulse duration

pulse duration formula Correct Answer period x number of cycles

what pulse duration is preferred for diagnostic imaging Correct Answer short

how is a short pulse duration achieved? Correct Answer damping layer helps to reduce # of cycles

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