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What is the period of the earth's rotation around the sun?
one year
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A top is spinning on a table. What is the period of the spinning top?
B.
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Which of the following waves is infrasonic?
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Identify the wave that is ultrasounic.
- A.
- it is greater than 20 kHz
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Which of these waves is ultrasounic and most useful in diagnostic sonography?
D.
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Identify all the waves that are inaudible. (More than 1 may be correct)
A. 4 MHz
B. 400 kHz
C. 28 Hz
D. 2 Hz
- A, B, D
- A&B are ultrasonic
- D is infrasonic
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Which of the following waves has the longest period?
- B.
- wave with the lowest frequency has the longest period
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of the four waves whose periods are listed below, which has the highest frequency?
- D.
- wave with the shortest period has the highest frequency
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Of the four wave whose frequencies are listed below, which has the shortest period?
- C.
- highest frequency will have the shortest wavelength
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Of the four waves whose periods are listed below, which has the lowest frequency?
- A.
- longest period will have the lowest frequency
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What are the units of wavelength?
millimeters
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What are the units of frequency?
hertz
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What are the units of intensity?
watts/cm2
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What are the units of propagation speed?
meters/second
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What are the units of period?
second
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What are the units of power?
watts
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Does the medium or sound source determine wavelength?
both
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Does the medium or sound source determine frequency?
sound source
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Does the medium or the sound source determine the intensity (initial)?
sound source
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Does the medium or the sound source determine the propagation speed?
medium
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Does the medium or the sound source determine the period?
sound source
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Does the medium or the sound source determine the power?
sound source
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Does the medium or the sound source determine the amplitude?
sound source
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Which of the following can be changed by the sonographer? wavelength, frequency, intensity, propagation speed, period, power, amplitude (initial)
intensity, power and amplitude
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True or False.
A wave with a frequency of 15,000 MHz is ultrasonic.
True. It is greater than 20,000 Hz
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True or false.
If the amplitude of a wave is increased to 3 times its original value, the intensity is increased by 6 times.
False. Intensity is proportional to the amplitude squared, if amplitude is tripled, we increase the intensity by a factor of 9
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What best describes the line identified by the letter A?
A. peak-to-peak amplitude
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What best describes the line identified by letter B?
E. none of the above
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What best describes the line identified by the letter C?
A. amplitude
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Which of the lines above, A, B, C or D, is most likely to be the reciprocal of frequency?
D.
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What best describes the line identified by the letter D?
D. wavelength
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What best describes the line identified by the letter D?
D. period
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Which of the lines above, A, B or C, is the most likely to be determined by the source and the medium?
B.
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True or False.
If the power of a wave is halved, the intensity is reduced to one-forth its original value
false, half the power = half the intensity
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True or False.
Propagation speed increases as frequency increases.
false, frequency is unrelated to speed
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Medium 1 has density of 9 and stiffnesss of 6.
Medium 2 has density of 8 and stiffness of 6.
In which medium will sound travel faster?
Medium 1, since both have same stiffness, the one with the greater density has the lower propagation speed
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Which of the following characteristics will create the fastest speed of sound?
- B.
- Speed is inversely proportional to density and directly proportional to stiffness
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Which of the following characteristics will create the slowest speed of sound?
- D.
- Speed is inversely proportional to density and directly proportional to stiffness
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If the power in a beam is 1 watt and the area is 5 cm2, what is the beam's intensity?
A. 5 W/cm2
B. 1 W/cm2
C. 0.2 W/cm2
D. 1 watt
- C.
- Intensity = watts/area
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If intensity remains the same while the power is doubled, what happened to the beam area?
doubled, if the intensity remains unchanged, then whatever happened to the power has to happen to the area.
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A sound beam travels a total of 10 cm in 2 seconds. What is the speed of the sound?
5 cm/sec
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True or False.
Propagation speed increases as frequency increases.
False
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True or False.
Propagation speed increases as frequency decreases.
False
-
True or False.
Propagation speed does not change as frequency increase
- True.
- Propagation speed and frequency are unrelated.
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What is the wavelength of 3 MHz sound in soft tissue?
- 0.51 mm
- 1.54 mm/3 MHz = 0.51 mm
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What is the wavelength of a wave with an unknown frequency traveling in soft tissue?
E. its the only one with the correct units
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The effects of sound waves on tissue in the body are called __________.
bioeffects
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What are the acoustic variables?
density, particle motion, temperature, pressure
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What are the acoustic parameters?
frequency, period, wavelength, propagation speed, amplitude, power, intensity
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The effects of tissue on sound waves are called __________.
acoustic propagation properties
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Th effects of a medium on an ultrasound wave are called __________.
acoustic propagation properties
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How are frequency and period related?
inversely
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How are amplitude and power related?
directly
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How are amplitude and intensity related?
directly
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How are power and intensity related?
directly
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How are wavelength and intensity related?
unrelated
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How are wavelength and frequency related?
inversely
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How are acoustic velocity and density related?
inversely
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How are elasticity and speed of sound related?
inversely
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How are acoustic velocity and compressibility related?
inversely
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How are stiffness and speed of sound related?
directly
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How are frequency and sound speed related?
unrelated
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How are frequency and intensity related?
unrelated
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How are power and frequency related?
unrelated
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