Search results
Results from the WOW.Com Content Network
Thus, for example, the CGS unit of pressure, barye, is related to the CGS base units of length, mass, and time in the same way as the SI unit of pressure, pascal, is related to the SI base units of length, mass, and time: 1 unit of pressure = 1 unit of force / (1 unit of length) 2 = 1 unit of mass / (1 unit of length × (1 unit of time) 2)
One difference between the Gaussian and SI systems is in the factor 4π in various formulas that relate the quantities that they define. With SI electromagnetic units, called rationalized, [3] [4] Maxwell's equations have no explicit factors of 4π in the formulae, whereas the inverse-square force laws – Coulomb's law and the Biot–Savart law – do have a factor of 4π attached to the r 2.
the total electric charge density (total charge per unit volume), ρ, and; the total electric current density (total current per unit area), J. The universal constants appearing in the equations (the first two ones explicitly only in the SI formulation) are: the permittivity of free space, ε 0, and; the permeability of free space, μ 0, and
Measure of a material's ability to conduct an electric current S/m L −3 M −1 T 3 I 2: scalar Electric potential: φ: Energy required to move a unit charge through an electric field from a reference point volt (V = J/C) L 2 M T −3 I −1: extensive, scalar Electrical resistance: R: Electric potential per unit electric current ohm (Ω = V/A ...
In the cgs-emu system, the unit of electric current is the abampere. The unit of current in the Heaviside–Lorentz system doesn't have a special name. The other units in the cgs-esu and Gaussian systems related to the statampere are: statcoulomb – the charge that passes in one second through any cross-section of a conductor carrying a steady ...
Speed or velocity is defined by the change in distance divided by a change in time. The derived unit m/s uses the base units of the SI system. [1] The derived unit km/h requires numerical factors to relate to the SI base units: 1000 m/km and 3600 s/h. In the cgs system, m/s is not a coherent derived unit.
An abampere of current in a circular path of one centimeter radius produces a magnetic field of 2π oersteds at the center of the circle. The name abampere was introduced by Kennelly in 1903 as a short name for the long name (absolute) electromagnetic cgs unit of current that was in use since the adoption of the cgs system in 1875. [ 3 ]
Heaviside–Lorentz units, like the Gaussian CGS units by which they generally differ by a factor of about 3.5, are frequently of rather inconvenient sizes. The ampere (coulomb/second) is reasonable unit for measuring currents commonly encountered, but the ESU/s, as demonstrated above, is far too small.