“electromagnetic radiation”的概念、定义、翻译、参考文献-科学参考

electromagnetic radiation

Physics

Energy resulting from the acceleration of electric charge and the associated electric fields and magnetic fields. The energy can be regarded as waves propagated through space (requiring no supporting medium) involving oscillating electric and magnetic fields at right angles to each other and to the direction of propagation. In a vacuum the waves travel with a constant speed (the speed of light) of 2.9979×10⁸ metres per second; if material is present they are slower. Alternatively, the energy can be regarded as a stream of photons travelling at the speed of light, each photon having an energy hc/λ‎, where h is the Planck constant, c is the speed of light, and λ‎ is the wavelength of the associated wave. A fusion of these apparently conflicting concepts is possible using the methods of quantum mechanics or wave mechanics. The characteristics of the radiation depend on its wavelength. See electromagnetic spectrum.

Astronomy

Energy arising from the acceleration of electrically charged entities (e.g. electrons). Electromagnetic radiation can be considered to be composed of waves or particles, since it displays properties of both; this is referred to as the wave–particle duality. Electromagnetic waves are composed of oscillating electric and magnetic fields which lie at right angles to each other and to the direction of travel. They propagate through a vacuum at the speed of light, c; the speed is slower when travelling through a medium such as air, water, or glass. The waves have a wavelength, λ‎, and a frequency, f or ν‎, which are linked by the equation c = f λ‎. Electromagnetic radiation may also be regarded as being composed of a stream of particles of zero mass called photons. The energy, E, of a photon is related to frequency by Planck’s formula E = hf, where h is the Planck constant. Hence the higher the frequency, the greater the energy of the radiation.

Space Exploration

The transfer of energy in the form of electromagnetic waves.

Chemistry

Energy resulting from the acceleration of electric charge and the associated electric fields and magnetic fields. The energy can be regarded as waves propagated through space (requiring no supporting medium) involving oscillating electric and magnetic fields at right angles to each other and to the direction of propagation. In a vacuum the waves travel with a constant speed (the speed of light) of 2.9979 × 10⁸ metres per second; if material is present they are slower. Alternatively, the energy can be regarded as a stream of photons travelling at the speed of light, each photon having an energy hc/λ‎, where h is the Planck constant, c is the speed of light, and λ‎ is the wavelength of the associated wave. A fusion of these apparently conflicting concepts is possible using the methods of quantum mechanics. The characteristics of the radiation depend on its wavelength. See electromagnetic spectrum.

Chemical Engineering

A form of energy in the form of electromagnetic waves, which are oscillating electric and magnetic fields at right angles to one another from the point of propagation. It includes radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays, which travel at the speed of light (2.9979 × 10⁸ m s⁻¹) in a vacuum but slower through materials.

Electronics and Electrical Engineering

Energy resulting from the acceleration of electric charge and the associated electric and magnetic fields. Transverse sinusoidal electric and magnetic fields are propagated at right angles to each other and to the direction of motion, the instantaneous values of the fields being related to the charge and current densities by Maxwell’s equations. These equations define the fields as electromagnetic waves propagated through free space at the speed of light (symbol c) which is a constant equal to
$2.997 924 58 \times 10^{8} metres per second$
Just as moving charged particles have associated wavelike features (see de Broglie waves) so electromagnetic radiation has a wave/particle duality: it may also be considered as a stream of particles (photons) that move at the speed of light, c, and have zero rest mass. Although wave motion is sufficient to explain the properties of reflection, refraction, and interference, quantum theory, which is concerned with the particulate nature of electromagnetic waves, must be used to explain phenomena, such as the photoelectric effect, that occur when radiation and matter interact.
The characteristics of the radiation depend on the frequency, ν, of the waves. The frequency, wavelength λ, and speed c are related by
$c = ν λ$
The photons have energy E related to the frequency ν by
$E = h ν$
where h is the Planck constant. Energy is exchanged between radiation and matter by absorption and emission in discrete amounts, termed quanta, the energy of each quantum being hν.
The total range of possible frequencies is defined as the electromagnetic spectrum (see Table 10, in the back matter). Radiowaves have the lowest frequencies; progressively higher frequencies are associated with infrared radiation, light, ultraviolet radiation, X-rays, through to gamma rays at the highest frequencies.

Geology and Earth Sciences

The range in radiation extending from wavelengths of less than 10⁻¹² m to more than 10³ m. In order of increasing wavelength are included cosmic ray photons, gamma rays, X-rays, ultraviolet radiation, visible light (violet to red), infrared radiation, microwaves, radio waves, and electric currents.

单词	electromagnetic radiation
释义	electromagnetic radiation Physics Energy resulting from the acceleration of electric charge and the associated electric fields and magnetic fields. The energy can be regarded as waves propagated through space (requiring no supporting medium) involving oscillating electric and magnetic fields at right angles to each other and to the direction of propagation. In a vacuum the waves travel with a constant speed (the speed of light) of 2.9979×10⁸ metres per second; if material is present they are slower. Alternatively, the energy can be regarded as a stream of photons travelling at the speed of light, each photon having an energy hc/λ‎, where h is the Planck constant, c is the speed of light, and λ‎ is the wavelength of the associated wave. A fusion of these apparently conflicting concepts is possible using the methods of quantum mechanics or wave mechanics. The characteristics of the radiation depend on its wavelength. See electromagnetic spectrum. Astronomy Energy arising from the acceleration of electrically charged entities (e.g. electrons). Electromagnetic radiation can be considered to be composed of waves or particles, since it displays properties of both; this is referred to as the wave–particle duality. Electromagnetic waves are composed of oscillating electric and magnetic fields which lie at right angles to each other and to the direction of travel. They propagate through a vacuum at the speed of light, c; the speed is slower when travelling through a medium such as air, water, or glass. The waves have a wavelength, λ‎, and a frequency, f or ν‎, which are linked by the equation c = f λ‎. Electromagnetic radiation may also be regarded as being composed of a stream of particles of zero mass called photons. The energy, E, of a photon is related to frequency by Planck’s formula E = hf, where h is the Planck constant. Hence the higher the frequency, the greater the energy of the radiation. Space Exploration The transfer of energy in the form of electromagnetic waves. Chemistry Energy resulting from the acceleration of electric charge and the associated electric fields and magnetic fields. The energy can be regarded as waves propagated through space (requiring no supporting medium) involving oscillating electric and magnetic fields at right angles to each other and to the direction of propagation. In a vacuum the waves travel with a constant speed (the speed of light) of 2.9979 × 10⁸ metres per second; if material is present they are slower. Alternatively, the energy can be regarded as a stream of photons travelling at the speed of light, each photon having an energy hc/λ‎, where h is the Planck constant, c is the speed of light, and λ‎ is the wavelength of the associated wave. A fusion of these apparently conflicting concepts is possible using the methods of quantum mechanics. The characteristics of the radiation depend on its wavelength. See electromagnetic spectrum. Chemical Engineering A form of energy in the form of electromagnetic waves, which are oscillating electric and magnetic fields at right angles to one another from the point of propagation. It includes radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays, which travel at the speed of light (2.9979 × 10⁸ m s⁻¹) in a vacuum but slower through materials. Electronics and Electrical Engineering Energy resulting from the acceleration of electric charge and the associated electric and magnetic fields. Transverse sinusoidal electric and magnetic fields are propagated at right angles to each other and to the direction of motion, the instantaneous values of the fields being related to the charge and current densities by Maxwell’s equations. These equations define the fields as electromagnetic waves propagated through free space at the speed of light (symbol c) which is a constant equal to $2.997 924 58 \times 10^{8} metres per second$ Just as moving charged particles have associated wavelike features (see de Broglie waves) so electromagnetic radiation has a wave/particle duality: it may also be considered as a stream of particles (photons) that move at the speed of light, c, and have zero rest mass. Although wave motion is sufficient to explain the properties of reflection, refraction, and interference, quantum theory, which is concerned with the particulate nature of electromagnetic waves, must be used to explain phenomena, such as the photoelectric effect, that occur when radiation and matter interact. The characteristics of the radiation depend on the frequency, ν, of the waves. The frequency, wavelength λ, and speed c are related by $c = ν λ$ The photons have energy E related to the frequency ν by $E = h ν$ where h is the Planck constant. Energy is exchanged between radiation and matter by absorption and emission in discrete amounts, termed quanta, the energy of each quantum being hν. The total range of possible frequencies is defined as the electromagnetic spectrum (see Table 10, in the back matter). Radiowaves have the lowest frequencies; progressively higher frequencies are associated with infrared radiation, light, ultraviolet radiation, X-rays, through to gamma rays at the highest frequencies. Geology and Earth Sciences The range in radiation extending from wavelengths of less than 10⁻¹² m to more than 10³ m. In order of increasing wavelength are included cosmic ray photons, gamma rays, X-rays, ultraviolet radiation, visible light (violet to red), infrared radiation, microwaves, radio waves, and electric currents.
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