Part 77-6.2

Part 7: Light and Radiation·66 entries

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Section 7-62 entries

7-6.1radiance 7-6.2spectral radiance

7-6.2

spectral radiance

URNurn:iso:std:iso:80000:-7:ed-2:en:item:7-6.2

Download RDF.jsonld .ttl

https://metanorma.github.io/isq-smart/quantities/part-7/t7-6.2
urn:iso:std:iso:80000:-7:ed-2:en:item:7-6.2

ISQ Identifiers

ISO

urn:iso:std:iso:80000:-7:ed-2:en:item:7-6.2

IEC

urn:iec:std:iec:80000-7:2019:::item:7-6.2

Designations

ENspectral radiance

FRluminance énergétique spectrique

FRradiance spectrique

Symbol

L_{e, λ}

(L_{λ})

Notation systems

Rendered

L_{e, λ}

Rendered

(L_{λ})

AsciiMath

L_("e",lambda)

AsciiMath

(L_lambda)

LaTeX

L_{\text{e} , \lambda}

LaTeX

( L_{\lambda} )

Definition

density of radiance with respect to wavelength, expressed by

L_{e, λ} = \frac{d L_{e}}{d λ}

where $L_{e}$ is radiance (radiance) in terms of wavelength $λ$ (ISO 80000-3: Space and time)

dérivée de la luminance énergétique par rapport à la longueur d'onde, exprimée par

L_{e, λ} = \frac{d L_{e}}{d λ}

où $L_{e}$ est la luminance énergétique (radiance) en fonction de la longueur d'onde $λ$ (ISO 80000-3: Space and time)

Units

\frac{W}{s r \cdot m^{2} \cdot n m}

watt per steradian square metre nanometre

View related quantities →

k g \cdot m^{- 1} \cdot s^{- 3} \cdot s r^{- 1}

kilogram per metre second cubed steradian

View related quantities →

Notes

For Planckian radiation,

L_{e, λ} (λ) = \frac{c (λ)}{4 π} ω_{λ} (λ) = h c_{0}^{2} \cdot f (λ, T)

where $c (λ)$ is phase speed (ISO 80000-3: Space and time) of electromagnetic radiation of a wavelength (ISO 80000-3: Space and time) $λ$ in a given medium, $ω_{λ} (λ)$ is spectral radiant energy density in terms of wavelength, $c_{0}$ is speed of light in vacuum (ISO 80000-1), $h$ is the Planck constant (ISO 80000-1), and

f (λ, T) = \frac{λ^{- 5}}{exp (c_{2} λ^{- 1} T^{- 1}) - 1}

where the radiation constant $c_{2} = h c / k$ .

The integral of (total) radiance is determined by the wavelength interval $(λ_{1}, λ_{2})$ under consideration:

L_{e} = \int_{λ_{1}}^{λ_{2}} L_{e, λ} (λ)

Pour un rayonnement de Planck,

L_{e, λ} (λ) = \frac{c (λ)}{4 π} ω_{λ} (λ) = h c_{0}^{2} \cdot f (λ, T)

où $c (λ)$ est la vitesse de phase (ISO 80000-3: Space and time) du rayonnement électromagnétique de longueur d'onde (ISO 80000-3: Space and time) $λ$ dans un milieu donné, $ω_{λ} (λ)$ est l'énergie rayonnante spectrique volumique en longueur d'onde, $c_{0}$ est la vitesse de la lumière dans le vide (ISO 80000-1), $h$ est la constante de Planck (ISO 80000-1) et

f (λ, T) = \frac{λ^{- 5}}{exp (c_{2} λ^{- 1} T^{- 1}) - 1}

où la constante de rayonnement $c_{2} = h c / k$ .

L'intégrale de la luminance énergétique (totale) est déterminée par l'intervalle de longueurs d'onde $(λ_{1}, λ_{2})$ considéré:

L_{e} = \int_{λ_{1}}^{λ_{2}} L_{e, λ} (λ)

Referenced by

luminance

Concept HierarchyPendrill (2024)

L²L² quantitiesLevel 0 · Kind

Broader concepts

◇ L² quantities

Ontology
isq:Quantity smart:TermEntry

Class Hierarchy

smart:Entity smart:TermEntryisq:Quantity

A physical quantity as defined in ISO/IEC 80000, with associated symbols, definitions, and units of measurement.

Instance IRI

isq:t7-6.2

Properties

isq:QuantityShape

Property	Value
rdf:type	isq:Quantity smart:TermEntry
dcterms:identifier	7-6.2
skosxl:prefLabel	"spectral radiance"@en
skosxl:altLabel	"L_("e",lambda)"@en"(L_lambda)"@en
skos:definition	density of radiance with respect to wavelength, expressed by [stem%unnumbered] ++++ L_("e",lambda) = ("d"L_"e")/("d"lam…
skos:note	For Planckian radiation, [stem%unnumbered] ++++ L_("e",lambda)(lambda) = (c(lambda))/(4pi) omega_lambda (lambda) = hc_0…
isq:hasUnit	W/(srm^2nm) (watt per steradian square metre nanometre)kgm^(-1)s^(-3)*sr^(-1) (kilogram per metre second cubed steradian)
isq:hasDimension	isq:Dimension
smart:hasBindingnessType	bindingness-type:normative
dcterms:isPartOf	isq:part-7

Related Entities

isq:QuantityShape isq:part-7 isq:Unit isq:Dimension isq:hasDimension smart:TermEntry