SPI Physics Board Review
Metric notations: giga, mega, kilo, hecto, deca, deci, centi, milli, micro, and nano
- CORRECT ANSWER-10 to the... Giga 9, mega 6, kilo 3, hecto 2, deca 1, deci
-1, centi -2, milli -3, micro -6, nano -9
Complimentary metric units: what goes with giga? Mega? Hecto? Deca? -
CORRECT ANSWER-Giga+nano
Mega+micro
Hecto+centi
Deca+deci
Sounds must travel though a (blank) it cant travel through a (blank) - CORRECT
ANSWER-Medium, vacuum
Sounds is a (blank) wave - CORRECT ANSWER-Mechanical, longitudinal
What are the three acoustic variables? What are their units? - CORRECT
ANSWER-1. Pressure: force/area, pascals
2. Density: mass/volume, kg/cm3
3. Distance: cm, feet, miles
Transverse versus longitudinal wave - CORRECT ANSWER-In a Transverse
wave the particles move perpendicular to the direction of the wave (think ocean
waves).
In longitudinal waves the particles move in the same direction as the wave
(bunched up slinky).
Compressions versus rarefactions - CORRECT ANSWER-Compressions are
areas of increased pressure or density whereas rarefactions are areas of
decreased pressure or density
Acoustic Parameters: what do these do? What are the 7 with ultrasound? -
CORRECT ANSWER-Acoustic parameters describe the features of a particular
wave (whereas acoustic variables determine which waves are sound waves).
The 7 acoustic variables we are concerned about with ultrasound are: period,
frequency, amplitude, power, intensity, speed and wavelength
,Acoustic parameters: Period
Definition, units, determined by source or medium, can sonographer change it,
relationships - CORRECT ANSWER-The time required to complete a single
cycle.
Units: seconds, microseconds, hours, any unit of time.
Determined by: sound source
Changed by sonographer: no
Relationships: period and frequency are reciprocals (inverse relationship); when
one goes up the other goes down.
Acoustic Parameters: Frequency
Definition, units, determined by source or medium, can sonographer change it,
typical values, relationships, what does freq affect? - CORRECT ANSWER-In
DMU the frequency of a wave is the number of cycles of an acoustic variable that
occur in one second.
Units: per second, 1/second = Hertz (Hertz is per second, 1,000/sec = kilohertz;
1,000,000/sec=megahertz).
Determined by sound source.
Changed by sonographer: no
Typical values 2 to 15 MHz
Relationships: frequency and period are inversely related.
Frequency affects penetration and axial resolution (image quality)
Ultrasound is a wave with a frequency greater than (blank) Hertz - CORRECT
ANSWER-20,000 Hz, (20kHz)
Audible sound is between (blank) and (blank) Hz - CORRECT ANSWER-20 and
20,000 Hz
Infrasound is sound with frequncies less than (blank) Hz - CORRECT
ANSWER-Less than 20 Hz
What time of relationship are period and frequency? What are their equations?
What are their complimentary units? - CORRECT ANSWER-Period and
frequency are reciprocals, having an inverse relationship (as one goes up the
other goes down);
,period (sec)=1/freq (Hz)
Freq (Hz) = 1/period (sec)
Freq (Hz) x period (sec) = 1
Complimentary units: sec & Hz; microseconds and MHz
What are the 3 bigness parameters which describe a sound beam's strength? -
CORRECT ANSWER-Amplitude, Power, Intensityl
Amplitude: what is it? Typical units? Determined by? Changed by sonographer? -
CORRECT ANSWER-Amplitude is the difference between the average value and
the maximum value of an acoustic variable.
Units: the units of the acoustic variables - pascals (pressure), grams per cm
cubed (density), and particle motion (units of distance); amplitude is usually
expressed in decibels.
Determined by: sound source
Changed by sonographer: yes
What is peak-to-peak amplitude and how does it compare the amplitude? -
CORRECT ANSWER-Amplitude is the difference between the average value and
the maximum vale of an acoustic variable. Peak-to-peak amplitude is the
difference between the maximum and minimum values of an acoustic variable.
Amplitude is half of the peak-to-peak amplitude.
Amplitude (blanks) as sound propagates through the body - CORRECT
ANSWER-Decreases
Power: what is it? Units? Determined by? Changed by sonographer? -
CORRECT ANSWER-Power is the rate that work is performed, or the rate of
energy transfer.
Units: Watts
Determined by: source
Changed by sonographer: Yes
What is the relationship between power & amplitude? Equation &
Example: what happens to power if amplitude is tripled? Halved? Doubled? -
CORRECT ANSWER-Power is proportional to the wave's amplitude squared.
, Power=amplitude squared
Example: if amplitude is tripled, power is increased by a factor of 9; if amplitude
is halved, the power js decreased by a factor of 4 (quartered); if amplitude is
doubled, the power is increased by a factor of 4.
Intensity: what is it? Equation? Units? Determined by? Changed by
sonographer? Typical values? - CORRECT ANSWER-Intensity is the
concentration of energy in a sound beam. Intensity depends on the power &
cross-sectional area of the beam.
Equation: intensity = power (watts)/beam area (cm squared)
Units: watts/cm squared; (watts is from power, cm squared is from beam area).
Determined by: sound source
Changed by sonographer: yes (since power can be changed by sonographer
then intensity can also be changed by the operator).
Typical values: 0.001 - 100 watts/cm squared
How are intensity and power related? What happens to intensity if power is
doubled? Quartered? - CORRECT ANSWER-Intensity and power are
proportional, or directly related. If one goes up, so does the other.
If power is doubled, intensity doubles.
If power is quartered, intensity is quartered.
How are intensity and amplitude related? Explain why. What happens to intensity
if amplitude is doubled? Quartered? - CORRECT ANSWER-Intensiry is
proportional to amplitude squared. We know this because intensity is proportional
to power, and power is equal to amplitude squared; therefore intensity is equal to
amplitude squared.
If amplitude is doubled, the intensity is increased by a factor of four.
If amplitude is quartered, then intensity is reduced by a factor of 16
Wavelength: what is it? Units? Determined by? Changed by sonographer?
Typical values? Equation - CORRECT ANSWER-Wavelength is the length or
distance of a single cycle.
Units: meters, mm, any unit of length.
Changed by sonographer: no (wavelength influences axial resolution-image
quality).
Typical values: 0.1-0.8 mm (in soft tissue)
Metric notations: giga, mega, kilo, hecto, deca, deci, centi, milli, micro, and nano
- CORRECT ANSWER-10 to the... Giga 9, mega 6, kilo 3, hecto 2, deca 1, deci
-1, centi -2, milli -3, micro -6, nano -9
Complimentary metric units: what goes with giga? Mega? Hecto? Deca? -
CORRECT ANSWER-Giga+nano
Mega+micro
Hecto+centi
Deca+deci
Sounds must travel though a (blank) it cant travel through a (blank) - CORRECT
ANSWER-Medium, vacuum
Sounds is a (blank) wave - CORRECT ANSWER-Mechanical, longitudinal
What are the three acoustic variables? What are their units? - CORRECT
ANSWER-1. Pressure: force/area, pascals
2. Density: mass/volume, kg/cm3
3. Distance: cm, feet, miles
Transverse versus longitudinal wave - CORRECT ANSWER-In a Transverse
wave the particles move perpendicular to the direction of the wave (think ocean
waves).
In longitudinal waves the particles move in the same direction as the wave
(bunched up slinky).
Compressions versus rarefactions - CORRECT ANSWER-Compressions are
areas of increased pressure or density whereas rarefactions are areas of
decreased pressure or density
Acoustic Parameters: what do these do? What are the 7 with ultrasound? -
CORRECT ANSWER-Acoustic parameters describe the features of a particular
wave (whereas acoustic variables determine which waves are sound waves).
The 7 acoustic variables we are concerned about with ultrasound are: period,
frequency, amplitude, power, intensity, speed and wavelength
,Acoustic parameters: Period
Definition, units, determined by source or medium, can sonographer change it,
relationships - CORRECT ANSWER-The time required to complete a single
cycle.
Units: seconds, microseconds, hours, any unit of time.
Determined by: sound source
Changed by sonographer: no
Relationships: period and frequency are reciprocals (inverse relationship); when
one goes up the other goes down.
Acoustic Parameters: Frequency
Definition, units, determined by source or medium, can sonographer change it,
typical values, relationships, what does freq affect? - CORRECT ANSWER-In
DMU the frequency of a wave is the number of cycles of an acoustic variable that
occur in one second.
Units: per second, 1/second = Hertz (Hertz is per second, 1,000/sec = kilohertz;
1,000,000/sec=megahertz).
Determined by sound source.
Changed by sonographer: no
Typical values 2 to 15 MHz
Relationships: frequency and period are inversely related.
Frequency affects penetration and axial resolution (image quality)
Ultrasound is a wave with a frequency greater than (blank) Hertz - CORRECT
ANSWER-20,000 Hz, (20kHz)
Audible sound is between (blank) and (blank) Hz - CORRECT ANSWER-20 and
20,000 Hz
Infrasound is sound with frequncies less than (blank) Hz - CORRECT
ANSWER-Less than 20 Hz
What time of relationship are period and frequency? What are their equations?
What are their complimentary units? - CORRECT ANSWER-Period and
frequency are reciprocals, having an inverse relationship (as one goes up the
other goes down);
,period (sec)=1/freq (Hz)
Freq (Hz) = 1/period (sec)
Freq (Hz) x period (sec) = 1
Complimentary units: sec & Hz; microseconds and MHz
What are the 3 bigness parameters which describe a sound beam's strength? -
CORRECT ANSWER-Amplitude, Power, Intensityl
Amplitude: what is it? Typical units? Determined by? Changed by sonographer? -
CORRECT ANSWER-Amplitude is the difference between the average value and
the maximum value of an acoustic variable.
Units: the units of the acoustic variables - pascals (pressure), grams per cm
cubed (density), and particle motion (units of distance); amplitude is usually
expressed in decibels.
Determined by: sound source
Changed by sonographer: yes
What is peak-to-peak amplitude and how does it compare the amplitude? -
CORRECT ANSWER-Amplitude is the difference between the average value and
the maximum vale of an acoustic variable. Peak-to-peak amplitude is the
difference between the maximum and minimum values of an acoustic variable.
Amplitude is half of the peak-to-peak amplitude.
Amplitude (blanks) as sound propagates through the body - CORRECT
ANSWER-Decreases
Power: what is it? Units? Determined by? Changed by sonographer? -
CORRECT ANSWER-Power is the rate that work is performed, or the rate of
energy transfer.
Units: Watts
Determined by: source
Changed by sonographer: Yes
What is the relationship between power & amplitude? Equation &
Example: what happens to power if amplitude is tripled? Halved? Doubled? -
CORRECT ANSWER-Power is proportional to the wave's amplitude squared.
, Power=amplitude squared
Example: if amplitude is tripled, power is increased by a factor of 9; if amplitude
is halved, the power js decreased by a factor of 4 (quartered); if amplitude is
doubled, the power is increased by a factor of 4.
Intensity: what is it? Equation? Units? Determined by? Changed by
sonographer? Typical values? - CORRECT ANSWER-Intensity is the
concentration of energy in a sound beam. Intensity depends on the power &
cross-sectional area of the beam.
Equation: intensity = power (watts)/beam area (cm squared)
Units: watts/cm squared; (watts is from power, cm squared is from beam area).
Determined by: sound source
Changed by sonographer: yes (since power can be changed by sonographer
then intensity can also be changed by the operator).
Typical values: 0.001 - 100 watts/cm squared
How are intensity and power related? What happens to intensity if power is
doubled? Quartered? - CORRECT ANSWER-Intensity and power are
proportional, or directly related. If one goes up, so does the other.
If power is doubled, intensity doubles.
If power is quartered, intensity is quartered.
How are intensity and amplitude related? Explain why. What happens to intensity
if amplitude is doubled? Quartered? - CORRECT ANSWER-Intensiry is
proportional to amplitude squared. We know this because intensity is proportional
to power, and power is equal to amplitude squared; therefore intensity is equal to
amplitude squared.
If amplitude is doubled, the intensity is increased by a factor of four.
If amplitude is quartered, then intensity is reduced by a factor of 16
Wavelength: what is it? Units? Determined by? Changed by sonographer?
Typical values? Equation - CORRECT ANSWER-Wavelength is the length or
distance of a single cycle.
Units: meters, mm, any unit of length.
Changed by sonographer: no (wavelength influences axial resolution-image
quality).
Typical values: 0.1-0.8 mm (in soft tissue)
