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.
By Elisabeth Dahl. The hertz is a familiar unit in the measurement of electricity--as common a word at home supply stores as amp or volt. Like some other units of measure, the hertz (abbreviated Hz) was named after an accomplished scientist. A hertz is an international measure of electrical frequency, with 1 Hz being one cycle per second.