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  2. Impedance of free space - Wikipedia

    en.wikipedia.org/wiki/Impedance_of_free_space

    The impedance of free space (that is, the wave impedance of a plane wave in free space) is equal to the product of the vacuum permeability μ 0 and the speed of light in vacuum c 0. Before 2019, the values of both these constants were taken to be exact (they were given in the definitions of the ampere and the metre respectively), and the value ...

  3. F-space - Wikipedia

    en.wikipedia.org/wiki/F-space

    In functional analysis, an F-space is a vector space over the real or complex numbers together with a metric: such that Scalar multiplication in X {\displaystyle X} is continuous with respect to d {\displaystyle d} and the standard metric on R {\displaystyle \mathbb {R} } or C . {\displaystyle \mathbb {C} .}

  4. Free-space path loss - Wikipedia

    en.wikipedia.org/wiki/Free-space_path_loss

    In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]

  5. Vacuum permittivity - Wikipedia

    en.wikipedia.org/wiki/Vacuum_permittivity

    Here, q 1 and q 2 are the charges, r is the distance between their centres, and the value of the constant fraction / is approximately 9 × 10 9 N⋅m 2 ⋅C −2. Likewise, ε 0 appears in Maxwell's equations , which describe the properties of electric and magnetic fields and electromagnetic radiation , and relate them to their sources.

  6. List of electromagnetism equations - Wikipedia

    en.wikipedia.org/wiki/List_of_electromagnetism...

    Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.

  7. Hilbert space - Wikipedia

    en.wikipedia.org/wiki/Hilbert_space

    the sequence { f n | n ∈ Z} with f n (x) = exp(2πinx) forms an orthonormal basis of the complex space L 2 ([0, 1]); In the infinite-dimensional case, an orthonormal basis will not be a basis in the sense of linear algebra; to distinguish the two, the latter basis is also called a Hamel basis. That the span of the basis vectors is dense ...

  8. Gravitational constant - Wikipedia

    en.wikipedia.org/wiki/Gravitational_constant

    According to Newton's law of universal gravitation, the magnitude of the attractive force (F) between two bodies each with a spherically symmetric density distribution is directly proportional to the product of their masses, m 1 and m 2, and inversely proportional to the square of the distance, r, directed along the line connecting their centres of mass: =.

  9. Phase space - Wikipedia

    en.wikipedia.org/wiki/Phase_space

    For mechanical systems, the phase space usually consists of all possible values of the position and momentum parameters. It is the direct product of direct space and reciprocal space. [clarification needed] The concept of phase space was developed in the late 19th century by Ludwig Boltzmann, Henri Poincaré, and Josiah Willard Gibbs. [1]