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Alternative definitions. ELF is a subradio frequency. [14] Some medical peer reviewed journal articles refer to ELF in the context of "extremely low frequency (ELF) magnetic fields (MF)" with frequencies of 50 Hz [15] and 50–80 Hz. [16] United States Government agencies, such as NASA, describe ELF as non-ionizing radiation with frequencies ...
Shortwave. [edit] Shortwave (1.6 to 30 MHz) diathermy (where EM waves are used to produce heat) can be used as a therapeutic technique for its analgesic effect and deep muscle relaxation, but has largely been replaced by ultrasound. Temperatures in muscles can increase by 4–6 °C, and subcutaneous fat by 15 °C.
Infrasound, sometimes referred to as low frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz, as defined by the ANSI/ASA S1.1-2013 standard). [1] Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be ...
One terahertz is 10 12 Hz or 1,000 GHz. Wavelengths of radiation in the terahertz band correspondingly range from 1 mm to 0.1 mm = 100 μm. Because terahertz radiation begins at a wavelength of around 1 millimeter and proceeds into shorter wavelengths, it is sometimes known as the submillimeter band, and its radiation as submillimeter waves ...
The commonly stated range of human hearing is 20 to 20,000 Hz. [6][7][note 1] Under ideal laboratory conditions, humans can hear sound as low as 12 Hz [8] and as high as 28 kHz, though the threshold increases sharply at 15 kHz in adults, corresponding to the last auditory channel of the cochlea. [9] The human auditory system is most sensitive ...
Extremely high frequency is the International Telecommunication Union designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the far infrared band, the lower part of which is the terahertz band. Radio waves in this band have wavelengths from ...
Non-ionizing radiation. Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum (photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. [1] Instead of producing charged ions when passing through matter, non ...
Brown note. The brown note, also sometimes called the brown frequency or brown noise, is a hypothetical infrasonic frequency capable of causing fecal incontinence by creating acoustic resonance in the human bowel. Considered an urban myth, the name is a metonym for the common color of human faeces. Attempts to demonstrate the existence of a ...