PhysicalConstant

Notable physical constants.

Entity["PhysicalConstant",name] or

represents an entity of type "PhysicalConstant".

[prop]

gives the value of a specified property.

[{propi,}]

gives the value of a list of properties.

EntityClass["PhysicalConstant",{propispeci,}]

represents a class of entities with values of propi defined by speci.

Sample Entities

Sample Entity Classes

Properties

  • AbbreviationCodeabbreviation code
    AlternateNamesalternate names
    ASCIIDescriptionASCII description
    Classesclasses
    ConjecturedValueAssociationconjectured value association
    ConjecturedValuesconjectured values
    Descriptiondescription
    EntityClassesentity classes
    EqualMagnitudeConstantsequalmagnitude constants
    EquivalentFormsequivalent forms
    ExternalLinkexternal link
    LevyLeblondClassLévyLeblond class
    Namename
    PrimarySourceprimary source
    Quantityquantity
    RelativeUncertaintyrelative uncertainty
    SeriesExpansionValueAssociationseries expansion value association
    SeriesExpansionValuesseries expansion values
    StandardUncertaintystandard uncertainty
    StandardYearstandard year
    Symbolsymbol
    Valuevalue
    ValueAssociationvalue association
    Valuesvalues
    Variantsvariants
    VariantTablevariant table

Details

  • "PhysicalConstant" entities include constants from physics, chemistry and astronomy whose values are characteristic of the universe, correspond to characteristics of our solar system, etc.
  • "PhysicalConstant" entity classes include classifications based on physical quantity, standards authority and exactness of definition.
  • Some properties are available for the "PhysicalConstant" entity type as a whole and can be given using the form EntityValue["PhysicalConstant",property]. Such properties include:
  • "Properties"the list of available properties
    "PropertyCanonicalNames"the standard names of available properties
    "SampleEntities"a sample list of available entities (typically of length 10)
    "SampleEntityClasses"a sample list of available entity classes (typically of length 10)
    "EntityCount"number of entities available
    "Entities"the list of available entities
    "EntityCanonicalNames"the standard names of available entities
    "EntityClasses"the list of available entity classes
    "EntityClassCanonicalNames"the standard names of available entity classes
    "PropertyClasses"the list of available property classes
    "PropertyClassCanonicalNames"the standard names of available property classes
    "PropertyCount"number of properties available
  • The following annotations can be used in the third argument of EntityValue["PhysicalConstant",property,annotation]:
  • "Source"source information for the property
    "Date"the date associated with the entity-property value (if any)
    "EntityAssociation"an association of entities and entity-property values
    "PropertyAssociation"an association of properties and entity-property values
    "EntityPropertyAssociation"an association in which the specified entities are keys, and values are a nested association of properties and entity-property values
    "PropertyEntityAssociation"an association in which the specified properties are keys, and values are a nested association of entities and entity-property values
    "Dataset"a dataset in which the specified entities are keys, and values are an association of property names and entity-property values
  • The following annotations can be used in the second argument of EntityValue[property,annotation]:
  • "Qualifiers"the list of possible qualifiers for the property
    "QualifierValues"the list of possible values that can be given to each qualifier
    "DefaultQualifierValues"the list of default values for the property's qualifiers
    "Description"a brief textual description of the property
    "Definition"a detailed textual definition of the property
    "PhysicalQuantity"the physical quantity associated with the entity-property value
    "Unit"the unit associated with the entity-property value
  • A qualifier value of Automatic indicates that an applicable format of values can be used; e.g. for the "Date" qualifier, this includes a proper date or date span.

Examples

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Basic Examples  (4)

Use for entity class discovery:

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Find a property value for an entity:

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Find conjectured values for the fine-structure constant:

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Retrieve a dataset of all available properties for an entity:

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Retrieve physical constants with exact values:

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Compare with the precomputed entity class:

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Applications  (1)