Some taxes are inadvertently hidden, but others are consciously designed that way to disguise the cost of government. Itâs easy to see why: the total U.S. tax burden is equal to 56 percent of annual personal consumption spending.
Thus, the volume is proportional to the amplitude of the sound wave. The frequency of a sound wave is perceived as pitch. Humans can detect pitches within the acoustic range of 20 to 20,000 Hz, but we can't detect ultrasound or infrasound.
hertz. A unit used to measure the frequency of vibrations and waves. One hertz is equal to one cycle per second.Radio waves are usually measured in megahertz, or millions of hertz.ertz. n. pl. hertz Abbr. Hz. A unit of frequency equal to one cycle per second. See Table at measurement.