Term

Definition
Two items that are not associated. 


Term
Directly related or directly proportional 

Definition
Two items that are associated such that when one item increases, the other increases. 


Term

Definition
Two items that are associated or affiliated. The relationship does not have to be specified. 


Term
Inversely related or inversely proportional. 

Definition
Two items are associated such that when one item increases, the other decreases. 


Term

Definition
When these two numbers are multiplied together they equal 1. 


Term
Increase by a factor means 

Definition
To multiply by that number. 


Term
Decrease by a factor means to 

Definition


Term
What are the prefixes for billions and billionths? 

Definition


Term
What are the prefixes for millions and millionths? 

Definition


Term
What are the prefixes for thousands and thousandths? 

Definition


Term
What are the prefixes for hundreds and hundredths? 

Definition


Term
What are the prefixes for tens and tenths? 

Definition


Term
What is scientific notation for 0.000001? 

Definition
ten to negative 6 or micro 


Term
When converting units if the unit gets larger the number must 

Definition


Term
billion also written as 10 to the 9th power has the prefix 

Definition


Term
Acoustic propagation properties 

Definition
the effects of the medium upon the sound wave 


Term

Definition
the effects of the sound wave upon the biologic tissue 


Term
What does a sound wave carry? 

Definition
a type of wave that carries energy, not matter, from place to place 


Term

Definition
vibration of a moving object 


Term
A sound wave is a series of 

Definition
compressions and rarefactions 


Term
Sound is what kind of wave? 

Definition
mechanical and longitudinal 


Term
The typical units for period are 

Definition
0.06 to 0.5 micro senconds usec which is the same as 0.6 x 10 to negative 7 to 5 x 10 to negative 7 


Term

Definition


Term
Can period be changed by the sonographer? 

Definition


Term
The units for frequency are 

Definition
hertz Hz same as per second 


Term
Frequency is determined by 

Definition


Term
Typical units for frequency are 

Definition


Term
A wave with a frequency exceeding 20,000 Hz or 20kHz 

Definition


Term
Sound with a frequency between 20 Hz and 20,000 Hz 

Definition


Term
Sound with frequencies less than 20Hz 

Definition


Term
This "bigness" parameter amplitude may be expressed in 

Definition


Term

Definition
The rate that sound travels through a medium 


Term
Units for propagation speed 

Definition
m/sec or mm/us (micro second) 


Term
Propagation speed is determined by 

Definition
the medium only
density and stiffness 


Term
Can the propagation speed be changed by the sonographer? 

Definition
No because it is determined only by the media 


Term

Definition
when two waves overlap at the same location and time 


Term
Constructive interference 

Definition
In phase waves combine to form a wave greater than the original two waves 


Term

Definition
out of phase waves interfere and cause the amplitude of the new wave to be less than the original waves 


Term

Definition
The difference between the maximum value and the average or undisturbed value of an acoustic variable. 


Term
Units of amplitude can be any of the acoustic variables such as 

Definition
pressure  pascals or density  g/cm cubed (3) Particle motion  distance dB decibels 


Term
Typical values of amplitude are 

Definition
1  3 million pascals same as 1 MPa to 3 MPa 


Term
Amplitude is initially determined by 

Definition
the sound source, however, amplitude decreases as sound propagates through the body. The rate at which amplitude decreases as sound propagates depends on the characteristics of both the sound wave and the MEDIUM. 


Term
Can the amplitude be controlled by the sonographer? 

Definition


Term
What is peak to peak amplitude? 

Definition
The difference between maximum and minimum values of an acoustic variable. 


Term
The rate at which energy is performed is 

Definition


Term

Definition


Term
The typical values for power are 

Definition
0.004 to 0.090 watts (4 to 90 milliwatts) 


Term
Power is determined initially by 

Definition
the sound source. However power decreases as sound propagates through the body. 


Term
Can the sonographer adjust the power? 

Definition


Term
Power is proportional to the amplitude 

Definition
SQUARED
if the sonographer increases the amplitude of a wave by a factor of 3 the power is increased 9 fold 3 x 3 =9 AMPLITUDE SQUARED 


Term
If a sonographer decreases the amplitude of a wave to 1/2 of its original value how has the power changed? 

Definition
Power is proportional to the amplitude squared so the power is decreased to 1/4 or 25% of its original value. 


Term

Definition
the concentration of energy in a sound beam 


Term
The units for intensity are 

Definition
watts per square cm
watts from power and cm squared from beam area 


Term
Typical values for intensity are 

Definition
0.01 to 300 watts/cm squared 


Term
Intensity is determined initially by 

Definition
The sound source. However, intensity changes as sound propagates through the body. The rate at which intensity changes depends on the characteristics of the medium and the shape of the sound beam. 


Term
Is intensity adjustable by the sonographer? 

Definition


Term
Amplitude, power and intensity tend to be related how? 

Definition


Term
Intensity is proportional to 

Definition
power
If power doubles intensity doubles 


Term
Intensity is proportional to amplitude 

Definition
squared.
If a waves amplitude is doubled the intensity is increased four times. 


Term
Power and Intensity are related to amplitude 

Definition


Term
Mathematically intensity and power are 

Definition


Term
This parameter is the only one determined by both the source and the medium. 

Definition


Term

Definition
the distance or length of one complete cycle. 


Term

Definition


Term
Typical values of wavelength are 

Definition


Term
Wavelength is determined by 

Definition
both the source and the medium 


Term
Is wavelength adjustable by the sonographer? 

Definition


Term
What is the relationship between wavelength and frequency? 

Definition
As long as the wave remains in the same medium they are inversely related. 


Term
What is the wavelength of 1 MHz sound in soft tissue? 

Definition


Term
What is the rule that defines the relationship between frequency and wavelength of sound in soft tissue? 

Definition
Divide 1.54mm by the frequency in MHz 


Term

Definition
the distance that a sound wave travels through a medium in 1 second. 


Term
Units for propagation speed are 

Definition
meters/second or mm/micorsecond or any distance divided by time 


Term
Typical values for propagation speed are 

Definition
500 m/sec to 4000 m/sec depending on the tissue it is traveling through. 


Term
Propagation speed is determined by 

Definition


Term
Is the propagation speed adjustable by the sonographer? 

Definition
No
It is determined by the medium only 


Term
List the speed of sound in biologic tissue from slowest to fastest. 

Definition
lung > fat > soft tissue average > liver > blood > muscle > tendon > bone 


Term
The propagation speed of air 

Definition


Term
Speed of sound in soft tissue (including blood) 

Definition


Term
Propagation speed of tendon 

Definition


Term
Propagation speed of bone 

Definition


Term
Two characteristics determine the speed of sound in tissue they are 

Definition


Term
Stiffness and speed are related how? 

Definition
directly
if one goes up the other goes up 


Term
Density and speed are related how? 

Definition
Inversely
If density goes up speed goes down 

