DMS Physics Final Exam Questions With Complete
Solutions
what term do we use for the length of an US pulse?
spatial pulse length
what is the equation for SPL? what are the units
SPL= #n X lambda its units are (mm)
what are the units for PRF ?
kHz
If a sounds volume were to double in the loudness, how many
decibles does it go up by?
+3dB
What is defined as the maximum variation in an acoustic
variable and what are its units
amplitude, decibles
what controls on the US machine adjusts amplitude?
power/ gain
how is intensity defined?
concentration of power or energy in a certain area
what varies in time and space?
intensity
how do we define attenuation?
, loss of energy weakening of sound as it travels
what are three components of attenuation?
absorption, reflection, scattering
sound that hits a large smooth boundary at a 90 degree angle
will produce what?
specular reflection
what are the two types of scattering?
back and reliegh
What is IRC?
percentage of the sounds intensity that is reflected
what two factors are required for reflection?
90 degree angle and 2 different impedances
what medium in the body has the lowest impedance?
air
What medium in the body has the highest impedance?
bone
the bigger the impedance mismatch the bigger that
reflection
define refraction
bending of light or sound a it travels from one medium to
another
what is required for refraction to occur?
Solutions
what term do we use for the length of an US pulse?
spatial pulse length
what is the equation for SPL? what are the units
SPL= #n X lambda its units are (mm)
what are the units for PRF ?
kHz
If a sounds volume were to double in the loudness, how many
decibles does it go up by?
+3dB
What is defined as the maximum variation in an acoustic
variable and what are its units
amplitude, decibles
what controls on the US machine adjusts amplitude?
power/ gain
how is intensity defined?
concentration of power or energy in a certain area
what varies in time and space?
intensity
how do we define attenuation?
, loss of energy weakening of sound as it travels
what are three components of attenuation?
absorption, reflection, scattering
sound that hits a large smooth boundary at a 90 degree angle
will produce what?
specular reflection
what are the two types of scattering?
back and reliegh
What is IRC?
percentage of the sounds intensity that is reflected
what two factors are required for reflection?
90 degree angle and 2 different impedances
what medium in the body has the lowest impedance?
air
What medium in the body has the highest impedance?
bone
the bigger the impedance mismatch the bigger that
reflection
define refraction
bending of light or sound a it travels from one medium to
another
what is required for refraction to occur?
