What is a hertz a measurement of?

A hertz is a unit of measurement that specifically quantifies frequency. It represents the number of cycles per second of a periodic phenomenon. When dealing with waves, such as sound waves, electromagnetic waves, or other oscillatory systems, frequency describes how often these cycles occur within a second. For instance, if a sound wave vibrates 440 times per second, it has a frequency of 440 hertz. Understanding the concept of frequency is essential in various fields, including physics, engineering, and medical aesthetics, as it relates to the behavior of different forms of energy and signals.

The other options do not accurately reflect what a hertz measures. Voltage measures the potential difference in electric energy, resistance quantifies how much a material opposes the flow of electric current, while power refers to the rate at which energy is used or produced. Each of these concepts plays a critical role in electrical and mechanical systems, but none are associated with the frequency of cycles, which is where hertz is pertinent.