Poynting theorem
E362048
The Poynting theorem is a fundamental principle in electromagnetism that expresses the conservation of electromagnetic energy by relating the flow of energy, energy density, and work done on charges.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Poynting theorem canonical | 3 |
How this entity was disambiguated
This entity first appeared as the object of triple T3487899 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Poynting theorem Context triple: [Poynting vector, isComponentOf, Poynting theorem]
-
A.
Poynting vector
The Poynting vector is a fundamental quantity in electromagnetism that represents the directional energy flux (power per unit area) carried by an electromagnetic field.
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B.
Maxwell's equations
Maxwell's equations are the fundamental set of four equations in classical electromagnetism that describe how electric and magnetic fields are generated and interact with charges and currents.
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C.
Ampère–Maxwell law
The Ampère–Maxwell law is one of Maxwell’s equations that relates magnetic fields to electric currents and changing electric fields, thereby introducing the concept of displacement current and enabling the prediction of electromagnetic waves.
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D.
Maxwell stress tensor
The Maxwell stress tensor is a mathematical construct in classical electromagnetism that represents how electric and magnetic fields transmit mechanical stresses, such as pressure and tension, through space and matter.
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E.
Ampère's force law
Ampère's force law is a fundamental principle in electromagnetism that quantifies the mechanical force between electric currents in conductors.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Poynting theorem Target entity description: The Poynting theorem is a fundamental principle in electromagnetism that expresses the conservation of electromagnetic energy by relating the flow of energy, energy density, and work done on charges.
-
A.
Poynting vector
The Poynting vector is a fundamental quantity in electromagnetism that represents the directional energy flux (power per unit area) carried by an electromagnetic field.
-
B.
Maxwell's equations
Maxwell's equations are the fundamental set of four equations in classical electromagnetism that describe how electric and magnetic fields are generated and interact with charges and currents.
-
C.
Ampère–Maxwell law
The Ampère–Maxwell law is one of Maxwell’s equations that relates magnetic fields to electric currents and changing electric fields, thereby introducing the concept of displacement current and enabling the prediction of electromagnetic waves.
-
D.
Maxwell stress tensor
The Maxwell stress tensor is a mathematical construct in classical electromagnetism that represents how electric and magnetic fields transmit mechanical stresses, such as pressure and tension, through space and matter.
-
E.
Ampère's force law
Ampère's force law is a fundamental principle in electromagnetism that quantifies the mechanical force between electric currents in conductors.
- F. None of above. chosen
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
physical law
ⓘ
theorem in electromagnetism ⓘ |
| appliesTo |
macroscopic Maxwell equations
ⓘ
time-varying electromagnetic fields ⓘ |
| assumes | validity of Maxwell equations ⓘ |
| category |
classical field theory
ⓘ
conservation laws ⓘ electromagnetic theory ⓘ |
| describes | conservation of electromagnetic energy ⓘ |
| expresses | local energy conservation for electromagnetic fields ⓘ |
| field | electromagnetism ⓘ |
| hasDifferentialForm | ∂u/∂t + ∇·S + J·E = 0 ⓘ |
| hasGeneralization | covariant energy-momentum conservation in electrodynamics ⓘ |
| hasIntegralForm | d/dt ∫_V u dV = - ∮_∂V S·dA - ∫_V J·E dV ⓘ |
| implies |
electromagnetic waves carry energy
ⓘ
energy can be transferred through the electromagnetic field ⓘ |
| involves |
Poynting vector
ⓘ
current density ⓘ electric field ⓘ magnetic field ⓘ |
| isAnalogousTo | conservation of mechanical energy ⓘ |
| isFormulatedInTermsOf |
Maxwell equations
ⓘ
linked to:
Maxwell's equations
Poynting vector S = E × H ⓘ electromagnetic energy density u ⓘ |
| isNamedAfter | John Henry Poynting ⓘ |
| isRelatedTo | continuity equation for energy ⓘ |
| isTaughtIn |
graduate electrodynamics courses
ⓘ
undergraduate electromagnetism courses ⓘ |
| isUsedIn |
antenna theory
ⓘ
electromagnetic wave theory ⓘ microwave engineering ⓘ optics ⓘ power flow calculations in transmission lines ⓘ radiation pressure analysis ⓘ waveguides analysis ⓘ |
| relates |
electromagnetic energy density
ⓘ
electromagnetic energy flux ⓘ work done on charges ⓘ |
| states | the decrease of electromagnetic energy in a volume equals the net energy flux out plus work done on charges ⓘ |
| usesSymbol |
E for electric field
ⓘ
H for magnetic field intensity ⓘ J for current density ⓘ S for Poynting vector ⓘ u for electromagnetic energy density ⓘ |
| yearProposed | 1884 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Poynting theorem Description of subject: The Poynting theorem is a fundamental principle in electromagnetism that expresses the conservation of electromagnetic energy by relating the flow of energy, energy density, and work done on charges.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.