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where is the length of the conductor, measured in metres [m], A is the cross-section area of the conductor measured in square metres [m 2], σ is the electrical conductivity measured in siemens per meter (S·m −1), and ρ is the electrical resistivity (also called specific electrical resistance) of the material, measured in ohm-metres (Ω·m ...
This is an essential property in electrical wiring systems. Copper has the highest electrical conductivity rating of all non-precious metals: the electrical resistivity of copper = 16.78 nΩ•m at 20 °C. The theory of metals in their solid state [7] helps to explain the unusually high electrical conductivity of copper.
Most metals have electrical resistance. In simpler models (non quantum mechanical models) this can be explained by replacing electrons and the crystal lattice by a wave-like structure. When the electron wave travels through the lattice, the waves interfere, which causes resistance. The more regular the lattice is, the less disturbance happens ...
These are called non-ohmic or non-linear, and their current–voltage curves are not straight lines through the origin. Resistance and conductance can still be defined for non-ohmic elements. However, unlike ohmic resistance, non-linear resistance is not constant but varies with the voltage or current through the device; i.e., its operating point.
In steady-state, ξ y will be strong enough to exactly cancel out the magnetic force, thus the electrons follow the straight arrow (dashed). The animation shows the action of a magnetic field on a beam of electric charges in vacuum, or in other terms, exclusively the action of the Lorentz force. This animation is an illustration of a typical ...
Paramagnetic materials are attracted to magnetic fields, hence have a relative magnetic permeability greater than one (or, equivalently, a positive magnetic susceptibility). The magnetic moment induced by the applied field is linear in the field strength, and it is rather weak. It typically requires a sensitive analytical balance to detect the ...
In electrostatics, a perfect conductor is an idealized model for real conducting materials. The defining property of a perfect conductor is that static electric field and the charge density both vanish in its interior. If the conductor has excess charge, it accumulates as an infinitesimally thin layer of surface charge. An external electric ...
In general, the force exerted upon a particle of charge q in the conductor by the electric field and magnetic field is given by (SI units): = (+), where is the charge on the particle, is the particle velocity and F is the Lorentz force. Here, however, the electric field is zero, so the force on the particle is =.