ARDMS Ultrasound Physics & Instrumentation Practice Exam

Which aspect of ultrasound refers to the time it takes for one cycle to occur?

1. Pulse duration

2. Frequency

3. Period

4. Wavelength

The correct answer is: Period

The aspect of ultrasound that refers to the time it takes for one cycle to occur is known as the period. The period is defined as the time interval needed for one complete cycle of a wave, measured in seconds. In ultrasound, this cycle corresponds to the complete sequence of compression and rarefaction of the sound wave produced by the transducer. To provide some additional context, pulse duration refers specifically to the duration of a single pulse emitted by the ultrasound machine. It is related but specifically tied to the duration of emitted sound pulses rather than the time for an individual cycle. Frequency, on the other hand, is the number of cycles that occur in one second, measured in Hertz (Hz). While frequency and period are inversely related (as frequency increases, period decreases), they represent different characteristics of the wave. Wavelength relates to the physical distance between successive peaks (or troughs) of the wave and is not directly related to the time it takes for a cycle to occur. Understanding these definitions is crucial in ultrasound physics, as they all relate to the behavior of sound waves, but the specific measurement of time for a cycle is captured by the concept of the period.