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 (Hz), A unit of measure of frequency equivalent to 1 cycle/sec; this term should not be used for radial (circular) frequency or for angular velocity, in which cases the term sec -1 should be used. [H.R. Hertz ]. (Hz) (herts) the SI unit of frequency, equal to one cycle per second.