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...transfer''' (VRT) is a method of modelling the propagation of polarized [[electromagnetic radiation]] in low density media. In contrast to [[scalar (mathematics)|sc ...s/scatterers present and must be calculated from their density-independent quantities, that is the [[attenuation coefficient]] vector, <math>\vec a</math>, is ca ...

{{Short description|Physics term; a conserved quantity of the electromagnetic field}} ...]], and therefore have limited physical significance. One of the conserved quantities (Lipkin's <math>Z^0</math>) has an intuitive physical interpretation and i ...

...e fluid flow vector field. When the energy-momentum tensor represents an [[electromagnetic field]], a Killing vector field does ''not necessarily'' preserve the elect ...

...a [[renormalization]] procedure, in order to be able to predict measurable quantities. The renormalization scheme can depend on the type of particles that are be ...ory, the Dirac field can interact with another field, for example with the electromagnetic field in quantum electrodynamics, and the strength of the interaction is me ...

...n observer moving with that frame to make measurements and define physical quantities. The [[covariance principle]] states the [[laws of physics]] should transfo ...he covariance group. In practice the equations for [[Electromagnetic force|electromagnetic]] and [[strong interaction|strong]] interactions ''are'' invariant, while t ...

...[[quantum field theory]], [[internal symmetries]] also result in conserved quantities. For example, the [[U(1)]] [[gauge transformation]] of [[Quantum electrodyn For comparison, the electromagnetic current produced by an electrically charged moving particle is <math>j^\mu ...

...st2=Wolf |first2=Emil |title=[[Principles of Optics|Principles of optics : electromagnetic theory of propagation, interference and diffraction of light]] |date=1980 | ...object space and <math>u'</math> and <math>n'</math> are the corresponding quantities in image space. The Smith–Helmholtz invariant implies that the lateral magn ...

...sity Press]] |location=Cambridge |year=2005 |isbn=0-521-02352-1}}</ref> An electromagnetic oscillator describes an oscillation of the electric field. Since the magnet ...ator|electromagnetic oscillator]]. For simplicity, it is assumed that this electromagnetic oscillator is in vacuum. An example is the [[plane wave]] given by ...

...st1=Jordan|first1= Edward |last2=Balmain|first2=Keith G.|year= 1968 |title=Electromagnetic Waves and Radiating Systems|edition= 2nd |publisher= Prentice-Hall | lccn=6 Retarded time accounts for the accounts for the time required for electromagnetic effects to propagate from point <math>\mathbf r'</math> to point <math>\mat ...

When an [[electromagnetic wave]] travels through a medium in which it gets attenuated (this is called {{Main|Electromagnetic wave equation}} ...

...e differently from static fields. This article is primarily concerned with electromagnetic multipole radiation, although the treatment of gravitational waves is simil ...ends more heavily on lower-order moments than on higher-order moments, the electromagnetic field can be approximated without knowing the structure in detail. ...

...deed, <math>\tau</math> is able to show the relationship between these two quantities and can lead to a greater understanding of the [[stellar structure|structur ...it is independent of any specific wavelength and absorbs along the entire electromagnetic spectrum. In that case, ...

...t=</math> means equality on the black-hole horizons (NEHs), and "hat" over quantities and operators (<math>\hat h^{ab}</math>, <math>\hat\nabla</math>, etc.) den ...\; (i=0,1,3,4)</math> (excluding <math>\Psi_2</math>) rather than Ricci-NP quantities <math>\Phi_{ij}</math>.<ref name="NP1" /> According to the Raychaudhuri-NP ...

...h integer spins. [[Photon|Photons]], which are the [[Quantum|quanta]] of [[Electromagnetic radiation|light]], have been long recognized as spin-1 [[Gauge boson|gauge An [[electromagnetic wave]] is said to have [[circular polarization]] when its [[electric]] and ...

...photon transport methods can be physical quantities such as [[Absorption (electromagnetic radiation)|absorption]], [[fluence]], [[reflectance]], or [[transmittance]] ...z axis and hence contribute to the specific absorption or related physical quantities as a [[Dirac delta function]]. Errors will result if absorption due to the ...

...lity]] can be used to diagnose the state of [[ionosphere]] by the use of [[electromagnetic pulses]]. ...nd the electric field, behave as plane waves. In other words, all physical quantities <math>f</math> will behave as an exponential function of time <math>t</math ...

Ettingshausen was the first to design an [[Electric machine|electromagnetic machine]], which used the electrical induction for power generation. He pro ...ve occasion in the following to make use of numerical expressions of these quantities, then we will choose for that purpose the symbol (n k) and will express it ...

...ies into the cavity or when the shape of the cavity is changed slightly, [[electromagnetic fields]] inside the cavity change accordingly. This means that all the reso ...no-optics. The underlying assumption of cavity perturbation theory is that electromagnetic fields inside the cavity after the change differ by a very small amount fro ...

...athematical expression|Hubble parameter]]. The [[Electromagnetic potential|electromagnetic 4-potential]] is The conserved quantities in the equations of motion ...

====General fundamental quantities==== For spectral quantities two definitions are in use to refer to the same quantity, in terms of frequ ...