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For example, the drum generator is based upon the figure to the bottom-right. A different implementation of this idea is the Faraday's disc , shown in simplified form on the right. In the Faraday's disc example, the disc is rotated in a uniform magnetic field perpendicular to the disc, causing a current to flow in the radial arm due to the ...
The resistance of a given conductor depends on the material it is made of, and on its dimensions. For a given material, the resistance is inversely proportional to the cross-sectional area. [1] For example, a thick copper wire has lower resistance than an otherwise-identical thin copper wire. Also, for a given material, the resistance is ...
Corona effect — Build-up of charges in a high-voltage conductor (common in AC transmission lines), which ionizes the air and produces visible light, usually purple. Dielectric polarization — Orientation of charges in certain insulators inside an external static electric field , such as when a charged object is brought close, which produces ...
The main properties of conductors are: [26] The electric field is zero inside a perfect conductor. Because charges are free to move in a conductor, when they are disturbed by an external electric field they rearrange themselves such that the field that their configuration produces exactly cancels the external electric field inside the conductor.
The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In normal (that is, non-superconducting) conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the ...
where is the length of the conductor, measured in metres (m), A is the cross-sectional 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 ...
A proton conductor, specifically, superionic ice, in a static electric field. In materials science, fast ion conductors are solid conductors with highly mobile ions. These materials are important in the area of solid state ionics, and are also known as solid electrolytes and superionic conductors. These materials are useful in batteries and ...
Conductors have a large density of free electrons whereas insulators do not; ions may be present in either. Given the good electrical and thermal conductivity in metals and the poor electrical and thermal conductivity in insulators, a natural starting point to estimate the thermal conductivity is to calculate the contribution of the conduction ...