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  2. Beta wave - Wikipedia

    en.wikipedia.org/wiki/Beta_wave

    Beta waves were discovered and named by the German psychiatrist Hans Berger, who invented electroencephalography (EEG) in 1924, as a method of recording electrical brain activity from the human scalp. Berger termed the larger amplitude, slower frequency waves that appeared over the posterior scalp when the subject's eye were closed alpha waves.

  3. Beta particle - Wikipedia

    en.wikipedia.org/wiki/Beta_particle

    A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus, known as beta decay. There are two forms of beta decay, β − decay and β + decay, which produce electrons and positrons, respectively.

  4. Ionizing radiation - Wikipedia

    en.wikipedia.org/wiki/Ionizing_radiation

    Ionizing radiation. Ionizing radiation (US, ionising radiation in the UK), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. [1] Some particles can travel up to 99% of the speed of light, and the electromagnetic waves ...

  5. Electromagnetic radiation - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_radiation

    As a wave, light is characterized by a velocity (the speed of light), wavelength, and frequency. As particles, light is a stream of photons. Each has an energy related to the frequency of the wave given by Planck's relation E = hf, where E is the energy of the photon, h is the Planck constant, 6.626 × 10 −34 J·s, and f is the frequency of ...

  6. Radiation - Wikipedia

    en.wikipedia.org/wiki/Radiation

    In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. [1][2] This includes: electromagnetic radiation consisting of photons, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ) particle radiation consisting of ...

  7. Relativistic Doppler effect - Wikipedia

    en.wikipedia.org/wiki/Relativistic_Doppler_effect

    A source of light waves moving to the right, relative to observers, with velocity 0.7 c. The frequency is higher for observers on the right, and lower for observers on the left. The relativistic Doppler effect is the change in frequency, wavelength and amplitude [1] of light, caused by the relative motion of the source and the observer (as in ...

  8. Beta decay - Wikipedia

    en.wikipedia.org/wiki/Beta_decay

    e. In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which an atomic nucleus emits a beta particle (fast energetic electron or positron), transforming into an isobar of that nuclide. For example, beta decay of a neutron transforms it into a proton by the emission of an electron accompanied by an antineutrino; or ...

  9. Particle radiation - Wikipedia

    en.wikipedia.org/wiki/Particle_radiation

    Particle radiation is the radiation of energy by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam. Due to the wave–particle duality, all moving particles also have wave character. Higher energy particles more easily ...