- Potential difference
physics, the potential difference or p.d. between two points is the difference of the points' scalar potential, equivalent to the line integral of the field strengthbetween the two points.
There are various types of potential difference related to the amount of
energyrequired to move an object from one place to another against various types of forces.
electrodynamics, the potential difference corresponds to the amount of work that would need to be done on a unit electric chargeto move it from one point to the other against an electric field. [ [http://www.sasked.gov.sk.ca/docs/physics/u3b23phy.html Physics 30 - Electricity - Electric Potential Difference ] ] P.d. is synonymous with voltage[ [http://www.powerstream.com/1922/battery_1922_WITTE/batteryfiles/definitions.htm Battery - Definitions ] ] and is measured in volts. It is the line integral of the electric field strengthbetween two points. [Pitt, V.H. (ed.), "The Penguin Dictionary of Physics", Penguin Books Ltd., 1977, ISBN 0140510710] Also, if "v" is the p.d. in volts, "w" is the work in joules (J), and "q" is the charge in coulombs (C), then:
mechanics, the " gravitational potentialdifference" between two points on Earth is related to the energy that would be required to move a unit massfrom one point to the other against the Earth's gravitational field. Units: joules per kilogram.
* In fluid systems the "potential difference" is the difference in
pressure. Units: pascals.
* In thermal systems the "potential difference" is the difference in
temperature. Units: kelvins.
In some engineering fields, "potential" is sometimes described as the '
across variable', whereas fluxis the ' through variable'. The product of the flux and the potential difference is the power, which is the time rate of change of energy.
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