ARDMS Ultrasound Physics & Instrumentation Practice Exam

Which term describes the distance over which one cycle occurs?

1. Amplitude

2. Wavelength

3. Frequency

4. Pulse duration

The correct answer is: Wavelength

The term that describes the distance over which one complete cycle of a wave occurs is wavelength. Wavelength is a fundamental concept in wave mechanics and refers to the spatial length of one cycle of a wave, which is measured from one peak (the crest) to the next peak (or equivalently from one trough to the next trough) in a continuous wave. In the context of ultrasound physics, understanding wavelength is critical because it directly influences image resolution and penetration—longer wavelengths penetrate deeper but may not provide the same level of detail as shorter wavelengths, which are associated with higher frequencies. This knowledge helps in selecting appropriate ultrasound settings for various diagnostic applications. The other terms relate to different aspects of wave behavior: amplitude relates to the height and intensity of the wave, frequency indicates how many cycles occur in a second, and pulse duration refers to the time over which a pulse of energy is emitted. While each of these terms plays a significant role in understanding ultrasound physics, it is the wavelength that specifically describes the physical length of a wave cycle.