# Shared Flashcard Set

## Details

US Physics (Edelman)
Chapter 1-3
83
Physics
Professional
06/17/2011

Term
 Unrelated
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
 Related or proportional
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
 Reciprocal relationship
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
 Divide by that number.
Term
 What are the prefixes for billions and billionths?
Definition
 Giga G & nano n
Term
 What are the prefixes for millions and millionths?
Definition
 mega M & micro u
Term
 What are the prefixes for thousands and thousandths?
Definition
 kilo k & milli m
Term
 What are the prefixes for hundreds and hundredths?
Definition
 hecto h & centi c
Term
 What are the prefixes for tens and tenths?
Definition
 deca da & deci d
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
 get smaller
Term
 billion also written as 10 to the 9th power has the prefix
Definition
 giga G
Term
 Acoustic propagation properties
Definition
 the effects of the medium upon the sound wave
Term
 Biological Effects
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
 Sound is created by
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 usecwhich is the same as0.6 x 10 to negative 7 to 5 x 10 to negative 7
Term
 Period is determined by
Definition
 the sound source
Term
 Can period be changed by the sonographer?
Definition
 NO
Term
 The units for frequency are
Definition
 hertz Hz same as per second
Term
 Frequency is determined by
Definition
 sound source
Term
 Typical units for frequency are
Definition
 2 to 15 MHz
Term
 A wave with a frequency exceeding 20,000 Hz or 20kHz
Definition
 Ultrasound
Term
 Sound with a frequency between 20 Hz and 20,000 Hz
Definition
 Audible sound
Term
 Sound with frequencies less than 20Hz
Definition
 Infrasound
Term
 This "bigness" parameter amplitude may be expressed in
Definition
 decibels dB
Term
 Propagation speed
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 onlydensity and stiffness
Term
 Can the propagation speed be changed by the sonographer?
Definition
 No because it is determined only by the media
Term
 Interference of waves
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
 Destructive interference
Definition
 out of phase waves interfere and cause the amplitude of the new wave to be less than the original waves
Term
 Amplitude is
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 - distancedB decibels
Term
 Typical values of amplitude are
Definition
 1 - 3 million pascalssame 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
 Yes
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
 Power
Term
 The units of power are
Definition
 watts
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
 Yes, WE HAVE THE POWER
Term
 Power is proportional to the amplitude
Definition
 SQUAREDif 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
 Intensity is
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
 Yes
Term
 Amplitude, power and intensity tend to be related how?
Definition
 Directly
Term
 Intensity is proportional to
Definition
 powerIf 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
 squared
Term
 Mathematically intensity and power are
Definition
 proportional or related
Term
 This parameter is the only one determined by both the source and the medium.
Definition
 Wavelength
Term
 Wavelength is
Definition
 the distance or length of one complete cycle.
Term
 Units of wavelength are
Definition
 mm, cm (distance)
Term
 Typical values of wavelength are
Definition
 0.15 to 0.8mm
Term
 Wavelength is determined by
Definition
 both the source and the medium
Term
 Is wavelength adjustable by the sonographer?
Definition
 No
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
 1.54mm
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
 Propagation speed is
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
 the medium only
Term
 Is the propagation speed adjustable by the sonographer?
Definition
 NoIt 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
 330 m/sec
Term
 Speed of sound in soft tissue (including blood)
Definition
 1,540 m/sec
Term
 Propagation speed of tendon
Definition
 1,850 m/sec
Term
 Propagation speed of bone
Definition
 2,000 to 4,000 m/sec
Term
 Two characteristics determine the speed of sound in tissue they are
Definition
 stiffness and density
Term
 Stiffness and speed are related how?
Definition
 directlyif one goes up the other goes up
Term
 Density and speed are related how?
Definition
 InverselyIf density goes up speed goes down
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