Kirchhoff's law


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Related to Kirchhoff's law: Kirchhoff's current law, Kirchhoff's first law

Kirchhoff's law

[′kərk‚hōfs ‚lȯ]
(electricity)
Either of the two fundamental laws dealing with the relation of currents at a junction and voltages around closed loops in an electric network; they are known as Kirchhoff's current law and Kirchhoff's voltage law.
(thermodynamics)
The law that the ratio of the emissivity of a heat radiator to the absorptivity of the same radiator is the same for all bodies, depending on frequency and temperature alone, and is equal to the emissivity of a blackbody. Also known as Kirchhoff's principle.
References in periodicals archive ?
Perfectly reflecting cavities never followed Kirchhoff's law. They are important however as they form the basis for many resonant devices [29-32].
Furthermore based on Kirchhoff's law, the emissivity in a certain polarization is equal to the absorptivity with the same polarization, which can be expressed as
Planck's derivation is seen as proof of Kirchhoff's Law. However, Robitaille points out that the above definition of Kirchhoff's Law is not complete and furthermore Robitaille maintains that the statement above should be called Stewart's Law as it was originally propounded by Stewart in 1858 [13]: "All too frequently, the simple equivalence between apparent spectral absorbance and emission is viewed as a full statement of Kirchhoff's law, ...
Given all that is involved relative to the validity of Kirchhoff's Law [1,2], Robert Johnson is to be commended, as the first duty of a scientist is to defend established science against possibly false charges.
Recently, the author has proposed two gedanken experiments in order to revisit Kirchhoff's law [15,16].
Moreover, because of Kirchhoff's law and the associated insistence that the radiation within a cavity must be independent of the nature of the walls, a tremendous void is created in the understanding of thermal emission.
In this work, the variable nature of cavity radiation is affirmed by addressing a Gedanken experiment which is often invoked to justify Kirchhoff's law, either in the classroom or within textbooks.
It is appropriate to begin this derivation by simply considering Kirchhoff's law [4, 5]
Based on this presentation, Kirchhoff's law is not valid and the constants of Planck and Boltzmann are not universal.
In reality, it would not be an overstatement to argue that Kirchhoff's law [15,16] constitutes the very core of accepted solar theory.
The problems with Kirchhoff's law were not simple to identify [61-66] and Planck himself [67, 68] echoed Kirchhoff's belief in the universal nature of radiation under conditions of thermal equilibrium [69, p.