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The examples include ground vibrations produced by elephants whose principal frequency component is around 15 Hz, and low- to medium-frequency substrate-borne vibrations used by most insect orders. [15] Many animal sounds, however, do fall within the frequency range detectable by a human ear, between 20 and 20,000 Hz. [16]
HF's position in the electromagnetic spectrum.. High frequency (HF) is the ITU designation [1] [2] for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters).
From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications.
Traditional classification of the frequency bands, that are associated to different functions/states of the brain and consist of delta, theta, alpha, beta and gamma bands. . Due to the limited capabilities of the early experimental/medical setup to record fast frequencies, for historical reason, all oscillations above 30 Hz were considered as high frequency and were difficult to investigate.
The bands are typically high frequency (HF) from 0.15 to 0.4 Hz, low frequency (LF) from 0.04 to 0.15 Hz, and the very low frequency (VLF) from 0.0033 to 0.04 Hz. [50] HF power reflects stimulation by the parasympathetic nervous system (PNS), whereas LF power reflects stimulation by both the sympathetic nervous system (SNS) and the PNS. [ 50 ]
Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the effects of man-made sources of electromagnetic fields like mobile phones, and the application of electromagnetic radiation toward therapies for the ...
Myosins and other mechanochemical enzymes which use chemical energy in the form of ATP to produce mechanical vibrations in cells may also contribute to sound wave generation in plant cells. These mechanisms may lead to overall nanomechanical oscillations of cytoskeletal components, which can generate both low and high frequency vibrations. [6]
Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in). Sound waves above 20 kHz are known as ultrasound and are not audible to ...