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| {{Merge|Scalar potential|date=September 2008}} | {{Merge|Scalar potential|date=September 2008}} | ||
| In ], the '''potential difference''' or '''p.d.''' between two points is the difference of the points' ], equivalent to the line integral of the ] |
In ], the '''potential difference''' or '''p.d.''' between two points is the difference of the points' ], equivalent to the line integral of the ] between the two points. | ||
| There are various types of potential difference related to the amount of ] required to move an object from one place to another against various types of ]s. | There are various types of potential difference related to the amount of ] required to move an object from one place to another against various types of ]s. | ||
| * in ], the potential difference corresponds to the amount of ] that would need to be done on a unit ] to move it from one point to the other against an ].<ref></ref> P.d. is synonymous with ] <ref></ref> and is measured in ]s. It is the line integral of the ] between two points.<ref>Pitt, V.H. (ed.), ''The Penguin Dictionary of Physics'', Penguin Books Ltd., 1977, ISBN 0140510710</ref> Also, if ''v'' is the p.d. in volts, ''w'' is the work in ]s (J), and ''q'' is the charge in ]s (C), then: | * in ], the potential difference corresponds to the amount of ] that would need to be done on a unit ] to move it from one point to the other against an ].<ref></ref> P.d. is synonymous with ] <ref></ref> and is measured in ]s. It is the line integral of the ] between two points.<ref>Pitt, V.H. (ed.), ''The Penguin Dictionary of Physics'', Penguin Books Ltd., 1977, ISBN 0140510710</ref> Also, if ''v'' is the p.d. in volts, ''w'' is the work in ]s (J), and ''q'' is the charge in ]s (C), then: | ||
| *:<math> v = { w \over q } {\mathrm{J} \over \mathrm{C}} \ \mathrm{or} \ {w \over q} \mathrm{V} </math> | *:<math> v = -{ w \over q } {\mathrm{J} \over \mathrm{C}} \ \mathrm{or} \ -{w \over q} \mathrm{V} </math> | ||
| *:{{main|Voltage}} | *:{{main|Voltage}} | ||
| * In ], the ''] difference'' between two points on Earth is related to the energy that would be required to move a unit ] from one point to the other against the Earth's ]. Units: joules per kilogram. | * In ], the ''] difference'' between two points on Earth is related to the energy that would be required to move a unit ] from one point to the other against the Earth's ]. Units: joules per kilogram. | ||
Revision as of 21:07, 22 October 2008
 | It has been suggested that this article be merged with Scalar potential. (Discuss) Proposed since September 2008. |
In 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 strength between the two points.
There are various types of potential difference related to the amount of energy required to move an object from one place to another against various types of forces.
- in electrodynamics, the potential difference corresponds to the amount of work that would need to be done on a unit electric charge to move it from one point to the other against an electric field. P.d. is synonymous with voltage and is measured in volts. It is the line integral of the electric field strength between two points. 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:
- Main article: Voltage
- In mechanics, the gravitational potential difference between two points on Earth is related to the energy that would be required to move a unit mass from 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 flux is the 'through variable'. The product of the flux and the potential difference is the power, which is the time rate of change of energy.
References
- Physics 30 - Electricity - Electric Potential Difference
- Battery - Definitions
- Pitt, V.H. (ed.), The Penguin Dictionary of Physics, Penguin Books Ltd., 1977, ISBN 0140510710