Ch. 2 Flashcards
______ is the amount of complete cycles per second.
a. wavelength
b. period
c. frequency
d. propagation speed
c. frequency
If frequency increases, each cycle (period) _______.
a. increases
b. decreases
c. remains unchanged
d. doubles
b. decreases
Wavelength is the ______ over which one cycle occurs.
a. time
b. length
c. area
d. power
b. length
Propagation speed is the speed at which a wave ______ through a medium.
a. cycles
b. refracts
c. travels
d. reflects
c. travels
Stiffer media have _____ sounds speeds.
a. lower
b. higher
c. stiffness does not change the prop. speed
d. sound cannot propagate through the stiffer media
b. higher
Frequency _______ wavelength.
a. is directly proportional to
b. is inversely proportional to
c. is equal to
d. has no bearing on
b. is inversely proportional to
Ultrasound pulses contain a range of frequencies called the ________.
a. fundamental frequencies
b. duty factor
c. pulse repetition frequencies
d. bandwidth
d. bandwidth
Pulsed ultrasound consists of _____ separated by ______ of time.
a. frequencies; cycles
b. pulses; cycles
c. pulses; gaps
d. cycles; pulses
c. pulses; gaps
Pulse repetition frequency (PRF) refers to the _____ of pulses occurring in one second.
a. speed
b. number
c. type
d. cycle
b. number
All of the following are acoustic variables except ______:
a. pressure
b. density
c. compression
d. particle vibration
c. compression
The fraction of time that pulsed ultrasound is on is called ____.
a. pulse repetition period
b. duty factor (DF)
c. period
d. spatial pulse length
b. duty factor (DF)
As sound travels, the reduction in amplitude and intensity of the wave is called _____.
a. scattering
b. attenuation
c. absorption
c. reflection
b. attenuation
What would be the frequency for a .22 mm wavelength in soft tissue?
a. 5.0 MHz
b. 7.0 MHz
c. 7.5 MHz
d. 3.5 MHz
b. 7.0 MHz
What is the pulse duration of a four-cycle pulse in a period of 0.5 us?
a. 0.2 us
b. 2.0 us
c. 1.25 us
d. .125 us
b. 2.0 us
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The velocity of sound in human soft tissue is assumed to be a constant. If you employ a 7.5 MHz transducer, what is the wavelength of the sound?
a. .11 mm
b. .20 mm
c. .025 mm
d. 1.1 mm
b. .20 mm
20 kHz is equal to ____ Hz.
a. 200
b. 2000
c. 20,000
d. 200,000
c. 20,000
1000 Hz is equal to ___ kHz.
a. 1
b. 10
c. 1000
d. .1
a. 1
What is the attenuation coefficient for a 5.0 MHz transducer in soft tissue?
a. .25 dB/cm
b. .1 dB/cm
c. 2.5 dB/cm
d. 10 dB/cm
c. 2.5 dB/cm
At what depth does a 3.0 MHz transducer have an attenuation of 9 dB?
a. 6.0 mm
b. .6 cm
c. 6.0 cm
d. .6 mm
c. 6.0 cm