Period and Frequency Flashcards
What is the range of periods commonly found in waves produced by ultrasound systems?
a. 0.001 to 1 s
b. 0.06 to 0.5 us
c. 0.2 to 1 ms
d. 10 to 100 ns
b. 0.06 to 0.5 us
With standard ultrasonic imaging, what happens to the period of a wave as it propagates?
a. increases
b. decreases
c. remains the same
c. remains the same
What determines the period of an ultrasonic wave?
a. the transducer
b. the medium through which the sound travels
c. both a. and b.
d. neither choice a. or b.
a. the transducer
Which of the following units are appropriate to describe the period of an acoustic wave? (more than one answer may be correct).
a. minutes
b. microseconds
c. meters
d. mm/us
e. cubic centimeters
a. minutes
b. microseconds
True or False?
The sonographer has the ability to alter the period of an ultrasonic wave that is produced by a basic transducer.
False
What term describes the number of cycles that an acoustic variable completes in a second?
a. period
b. frequency
c. pulse repetition period
d. variable rate
b. frequency
Which of the following cannot be considered a unit of frequency?
a. per day
b. cycles/sec
c. Hz
d. hertz
e. cycles
e. cycles
What is the range of frequencies emitted by transducers used in ultrasonic imaging?
a. 1 to 3 MHz
b. 1 to 1,000 kHz
c. -10,000 to + 10,000 Hz
d. 2,000,000 to 15,000,000 Hz
d. 2,000,000 to 15,000,000 Hz
What establishes the frequency of an ultrasound wave?
a. the transducer
b. the medium through which the sound travels
c. both a. and b.
d. neither choice a. nor b.
a. the transducer
True or False?
With standard ultrasound pulses, the frequency of the ultrasound changes significantly as the wave propagates through the body.
False
When a sonographer increases the maximum imaging depth during an exam, what happens to the frequency?
a. frequency increases
b. frequency decreases
c. remains unchanged
c. remains unchanged
Ultrasound is defined as a sound with a frequency of _____.
a. greater than 20,000 kHz
b. less than 1 kHz
c. greater than 10 MHz
d. greater than 0.02 MHz
d. greater than 0.02 MHz
Infrasound is defined as a sound with a frequency of ____.
a. greater than 20,000 kHz
b. less than 20 Hz
c. greater than 10 MHz
d. less than 0.02 MHz
b. less than 20 Hz
True or False?
Waves in the ultrasound range behave in the same general manner as sound waves that are audible.
True
What is characteristic of acoustic waves with frequencies exceeding 20,000 Hz when compared with waves having frequencies of less than 20,000 Hz?
a. they travel more effectively in soft tissue
b. they travel more rapidly
c. they attenuate less when traveling in soft tissue
d. humans can’t hear them
d. humans can’t hear them
