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The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is electrical conductance, measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (Ω ...
The SI unit of electrical resistivity is the ohm - metre (Ω⋅m). [1][2][3] For example, if a 1 m3 solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1 Ω, then the resistivity of the material is 1 Ω⋅m. Electrical conductivity (or specific conductance) is the reciprocal of ...
Ohm's law states that the electric current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, [ 1 ] one arrives at the three mathematical equations used to describe this relationship: [ 2 ] where I is the current through the conductor ...
However, resistance and conductance are extensive rather than bulk properties, meaning that they also depend on the size and shape of an object. For example, a wire's resistance is higher if it is long and thin, and lower if it is short and thick. All objects show some resistance, except for superconductors, which have a resistance of zero. The ...
Joule heating (also known as resistive, resistance, or Ohmic heating) is the process by which the passage of an electric current through a conductor produces heat.. Joule's first law (also just Joule's law), also known in countries of the former USSR as the Joule–Lenz law, [1] states that the power of heating generated by an electrical conductor equals the product of its resistance and the ...
The inverse of the resistance is known as the conductance. When we consider a metal of unit length and unit cross sectional area, the conductance is known as the conductivity, which is the inverse of resistivity. The Drude model attempts to explain the resistivity of a conductor in terms of the scattering of electrons (the carriers of ...
t. e. The Hall effect is the production of a potential difference (the Hall voltage) across an electrical conductor that is transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current. It was discovered by Edwin Hall in 1879. [1][2]
Two electrodes. Concrete electrical resistance can be measured by applying a current using two electrodes attached to the ends of a uniform cross-section specimen. Electrical resistivity is obtained from the equation: [1] R is the electrical resistance of the specimen, the ratio of voltage to current (measured in ohms, Ω) ℓ {\displaystyle \ell }