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  2. Poynting's theorem - Wikipedia

    en.wikipedia.org/wiki/Poynting's_theorem

    In electrodynamics, Poynting's theorem is a statement of conservation of energy for electromagnetic fields developed by British physicist John Henry Poynting. [1] It states that in a given volume, the stored energy changes at a rate given by the work done on the charges within the volume, minus the rate at which energy leaves the volume.

  3. List of optics equations - Wikipedia

    en.wikipedia.org/wiki/List_of_optics_equations

    Quantity (common name/s) (Common) symbol/s Defining equation SI units Dimension Poynting vector: S, N = = W m −2 [M][T] −3 Poynting flux, EM field power flow Φ S, Φ N = W

  4. Poynting vector - Wikipedia

    en.wikipedia.org/wiki/Poynting_vector

    The Poynting vector appears in Poynting's theorem (see that article for the derivation), an energy-conservation law: =, where J f is the current density of free charges and u is the electromagnetic energy density for linear, nondispersive materials, given by = (+), where

  5. Reciprocity (electromagnetism) - Wikipedia

    en.wikipedia.org/wiki/Reciprocity_(electromagnetism)

    For the special case of = , this gives a re-statement of conservation of energy or Poynting's theorem (since here we have assumed lossless materials, unlike above): The time-average rate of work done by the current (given by the real part of ) is equal to the time-average outward flux of power (the integral of the Poynting vector). By the same ...

  6. Maxwell stress tensor - Wikipedia

    en.wikipedia.org/wiki/Maxwell_stress_tensor

    All but the last term of can be written as the tensor divergence of the Maxwell stress tensor, giving: = +, As in the Poynting's theorem, the second term on the right side of the above equation can be interpreted as the time derivative of the EM field's momentum density, while the first term is the time derivative of the momentum density for ...

  7. List of theorems - Wikipedia

    en.wikipedia.org/wiki/List_of_theorems

    Post's theorem (mathematical logic) Poynting's theorem ; Preimage theorem (differential topology) Price's theorem (general relativity) Prime number theorem (number theory) Primitive element theorem (field theory) Principal axis theorem (linear algebra) Principal ideal theorem (algebraic number theory) Prokhorov's theorem (measure theory)

  8. Fresnel equations - Wikipedia

    en.wikipedia.org/wiki/Fresnel_equations

    The Poynting vector for a wave is a vector whose component in any direction is the irradiance (power per unit area) of that wave on a surface perpendicular to that direction. For a plane sinusoidal wave the Poynting vector is ⁠ 1 / 2 ⁠ ‍ Re{E × H ∗}, where E and H are due only to the

  9. John Henry Poynting - Wikipedia

    en.wikipedia.org/wiki/John_Henry_Poynting

    Mason Science College (demolished in 1964) John Henry Poynting FRS [1] (9 September 1852 – 30 March 1914 [2] [3]) was an English physicist.He was the first professor of physics at Mason Science College from 1880 to 1900, and then the successor institution, the University of Birmingham until his death.