Frequency refers to the number of times in each period of fluctuation, usually expressed in hertz (Hz). The higher the frequency, the shorter the cycle time and the denser the fluctuation. For example, high-pitched instruments have higher frequencies than low-pitched instruments because they produce faster fluctuations.
In physics and engineering, amplitude and frequency are important parameters of many phenomena, such as mechanical vibration, electromagnetic waves, optics, astronomy and so on. Understanding and applying these two parameters can help us to better explain and describe many phenomena in nature. For example, by understanding the amplitude and frequency of seismic waves, we can better understand and predict the nature and influence of earthquakes.