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The vacuum magnetic permeability (variously vacuum permeability, permeability of free space, permeability of vacuum, magnetic constant) is the magnetic permeability in a classical vacuum. It is a physical constant , conventionally written as μ 0 (pronounced "mu nought" or "mu zero").
μ 0 ≈ 12.566 × 10 −7 H/m is the magnetic constant, also known as the permeability of free space, ε 0 ≈ 8.854 × 10 −12 F/m is the electric constant, also known as the permittivity of free space, c is the speed of light in free space, [9] [10] The reciprocal of Z 0 is sometimes referred to as the admittance of free space and ...
where e is the elementary charge, ħ is the reduced Planck constant, c is the speed of light in vacuum, and ε 0 is the permittivity of free space. The fine-structure constant is fixed to the strength of the electromagnetic force. At low energies, α ≈ 1 / 137 , whereas at the scale of the Z boson, about 90 GeV, one measures α ≈ ...
The astronomical system of units, formerly called the IAU (1976) System of Astronomical Constants, is a system of measurement developed for use in astronomy.It was adopted by the International Astronomical Union (IAU) in 1976 via Resolution No. 1, [1] and has been significantly updated in 1994 and 2009 (see Astronomical constant).
The vacuum permittivity ε o (also called permittivity of free space or the electric constant) is the ratio D / E in free space. It also appears in the Coulomb force constant , k e = 1 4 π ε 0 {\displaystyle k_{\text{e}}={\frac {1}{\ 4\pi \varepsilon _{0}\ }}}
The standard acceleration of gravity or standard acceleration of free fall, often called simply standard gravity and denoted by ɡ 0 or ɡ n, is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is a constant defined by standard as 9.806 65 m/s 2 (about 32.174 05 ft/s 2).
A unit prefix is a specifier or mnemonic that is added to the beginning of a unit of measurement to indicate multiples or fractions of the units. Units of various sizes are commonly formed by the use of such prefixes.
In mathematics, sine and cosine are trigonometric functions of an angle.The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the ...