Period & Frequency

What term describes the number of cycles that an acoustic variable completes in a second?

frequency

is the reciprocal of period.

frequency

Ultrasound is defined as a sound with a frequency of

greater than 0.02 MHz

What is characteristic of acoustic waves with frequencies of less than 20 Hz when compared with waves having frequencies of more than 20 Hz?

humans can't hear them

Which of the following cannot be considered a unit of frequency?

сycles

Infrasound is defined as a sound with a frequency of

B. less than 20 Hz

What is characteristic of acoustic waves with frequencies exceeding 20,000 Hz when compared with waves having frequencies of less than 20,000 Hz?

D. humans can't hear them

The frequency with a duty factor of 0.1. wave is 5 MHz. The wave is then pulsed of a continuous acoustic What is the new frequency?

5 MHz

Compare two sound waves, A and B. The frequency of wave A is one-third that of wave B. How does the period of wave A compare with the period of wave B?

A is three times as long as B

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

What determines the period of an ultrasound wave?

A. the transducer

What establishes the frequency of an ultrasound wave?

A. the transducer

What is the range of periods commonly found in waves produced by ultrasound systems?

B. 0.06 to 0.5 ps

When a sonographer increases the maximum imaging depth during an exam, what happens to the frequency?

C. remains unchanged

What is the range of frequencies emitted by transducers used in ultrasonic imaging?

D. 2,000,000 to 15,000,000 Hz

True or False? With standard ultrasound pulses, the frequency of the ultrasound changes significantly as the wave propagates through the body.

False

True or False? The sonographer has the ability to alter the period of an ultrasound wave that is produced by a basic transducer.

False.

True or False? If the periods of two waves are the same, then the frequencies of the waves must also be the same.

True

True or False? The period of an ultrasound wave is related to the frequency and is the same, regardless of whether the wave is pulsed or continuous.

True

True or False? Waves in the ultrasound range behave in the same general manner as sound waves that are audible.

True.