Adult Echo. Test 1 Questions With 100% Correct Answers.

Sound Waves - mechanical vibrations that induce alternate refraction and compression of any physical medium through which they pass. -should travel in a straight line compression - when sound waves come close together, opposite of rarefaction rarefaction - when sound waves are farther apart, opposite of compression higher frequency - a higher this equals a higher resolution! transverse wave - perpendicular to the way it's traveling longitudinal wave - moving in the same direction frequency - in terms of acoustic variables it's described as Hertz (Hz) -means cycles per second! -humans can hear 20Hz-20Kz -Ultrasound is greater than 20Khz (above 20,000 Hz) -diagnostic ultrasound uses between 1 and 20Mhz wavelength - in terms of acoustic variables it's described as a measure of length or distance! (mm) -length of space over which one cycle occurs -dependent on frequency! -Higher frequency=shorter wavelength! amplitude - in terms of acoustic variables it's described as decibels!-loudness -may also be: pressure, density, temperature and particle motion velocity of propagation - the speed that a sound wave moves through the body (different for each type of tissue) ex. in bone, it's much faster than in lung tissue maximum variation - found in an acoustic variable, it is the difference between the average value and the maximum value of an acoustic variable (how tall/how much energy does that wave have)