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Human alpha rhythm has strong generators [clarification needed] in parieto-occipital areas [12] [13] which can be coherent with sources in the pulvinar and lateral geniculate nucleus. [14] They are generated in other neocortical areas as well. Oscillations in the alpha band called a mu wave can be found over the primary motor cortex. [15]
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. [5] They are generally produced in the process of alpha decay but may also be produced in other ways. Alpha particles are named after the first letter in the Greek alphabet, α.
A monochromatic wave (a wave of a single frequency) consists of successive troughs and crests, and the distance between two adjacent crests or troughs is called the wavelength. Waves of the electromagnetic spectrum vary in size, from very long radio waves longer than a continent to very short gamma rays smaller than atom nuclei.
Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing.
The lower part of this range may also be called microwaves or terahertz waves. This radiation is typically absorbed by so-called rotational modes in gas-phase molecules, by molecular motions in liquids, and by phonons in solids. The water in Earth's atmosphere absorbs so strongly in this range that it renders the atmosphere in effect opaque.
The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.1 Hz (and rarely to 0.001 Hz). People use this frequency range for monitoring earthquakes and volcanoes, charting rock and petroleum formations below the earth, and also in ballistocardiography and seismocardiography to study the ...
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 humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges, allowing some to even hear ultrasounds
This picture shows the four particles that are detectable in a cloud chamber : proton, electron, muon (probably) and alpha. Delta rays are seen associated with the proton track. A delta ray is characterized by very fast electrons produced in quantity by alpha particles or other fast energetic charged particles knocking orbiting electrons out of ...