Template:SI radiometry units
| Quantity | Unit | Dimension | Notes | ||
|---|---|---|---|---|---|
| Name | Symbol<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-e">Standards organizations recommend that radiometric quantities should be denoted with suffix "e" (for "energetic") to avoid confusion with photometric or photon quantities.</ref> | Name | Symbol | ||
| Radiant energy | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-alternative-symbol-radiometric">Alternative symbols sometimes seen: Template:Mvar or Template:Mvar for radiant energy, Template:Mvar or Template:Mvar for radiant flux, Template:Mvar for irradiance, Template:Mvar for radiant exitance.</ref> | joule | J | M⋅L2⋅T−2 | Energy of electromagnetic radiation. |
| Radiant energy density | Template:Math | joule per cubic metre | J/m3 | M⋅L−1⋅T−2 | Radiant energy per unit volume. |
| Radiant flux | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-alternative-symbol-radiometric"></ref> | watt | W = J/s | M⋅L2⋅T−3 | Radiant energy emitted, reflected, transmitted or received, per unit time. This is sometimes also called "radiant power", and called luminosity in astronomy. |
| Spectral flux | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu">Spectral quantities given per unit frequency are denoted with suffix "ν" (Greek letter nu, not to be confused with a letter "v", indicating a photometric quantity.)</ref> | watt per hertz | W/Hz | M⋅L2⋅T −2 | Radiant flux per unit frequency or wavelength. The latter is commonly measured in W⋅nm−1. |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda">Spectral quantities given per unit wavelength are denoted with suffix "λ".</ref> | watt per metre | W/m | M⋅L⋅T−3 | ||
| Radiant intensity | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-omega">Directional quantities are denoted with suffix "Ω".</ref> | watt per steradian | W/sr | M⋅L2⋅T−3 | Radiant flux emitted, reflected, transmitted or received, per unit solid angle. This is a directional quantity. |
| Spectral intensity | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | watt per steradian per hertz | W⋅sr−1⋅Hz−1 | M⋅L2⋅T−2 | Radiant intensity per unit frequency or wavelength. The latter is commonly measured in W⋅sr−1⋅nm−1. This is a directional quantity. |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | watt per steradian per metre | W⋅sr−1⋅m−1 | M⋅L⋅T−3 | ||
| Radiance | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-omega"></ref> | watt per steradian per square metre | W⋅sr−1⋅m−2 | M⋅T−3 | Radiant flux emitted, reflected, transmitted or received by a surface, per unit solid angle per unit projected area. This is a directional quantity. This is sometimes also confusingly called "intensity". |
| Spectral radiance Specific intensity |
Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | watt per steradian per square metre per hertz | W⋅sr−1⋅m−2⋅Hz−1 | M⋅T−2 | Radiance of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅sr−1⋅m−2⋅nm−1. This is a directional quantity. This is sometimes also confusingly called "spectral intensity". |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | watt per steradian per square metre, per metre | W⋅sr−1⋅m−3 | M⋅L−1⋅T−3 | ||
| Irradiance Flux density |
Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-alternative-symbol-radiometric"></ref> | watt per square metre | W/m2 | M⋅T−3 | Radiant flux received by a surface per unit area. This is sometimes also confusingly called "intensity". |
| Spectral irradiance Spectral flux density |
Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Irradiance of a surface per unit frequency or wavelength. This is sometimes also confusingly called "spectral intensity". Non-SI units of spectral flux density include jansky (Template:Val = Template:Val) and solar flux unit (Template:Val = Template:Val = Template:Val). |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
| Radiosity | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-alternative-symbol-radiometric"></ref> | watt per square metre | W/m2 | M⋅T−3 | Radiant flux leaving (emitted, reflected and transmitted by) a surface per unit area. This is sometimes also confusingly called "intensity". |
| Spectral radiosity | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Radiosity of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅m−2⋅nm−1. This is sometimes also confusingly called "spectral intensity". |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
| Radiant exitance | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-alternative-symbol-radiometric"></ref> | watt per square metre | W/m2 | M⋅T−3 | Radiant flux emitted by a surface per unit area. This is the emitted component of radiosity. "Radiant emittance" is an old term for this quantity. This is sometimes also confusingly called "intensity". |
| Spectral exitance | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Radiant exitance of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅m−2⋅nm−1. "Spectral emittance" is an old term for this quantity. This is sometimes also confusingly called "spectral intensity". |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
| Radiant exposure | Template:Math | joule per square metre | J/m2 | M⋅T−2 | Radiant energy received by a surface per unit area, or equivalently irradiance of a surface integrated over time of irradiation. This is sometimes also called "radiant fluence". |
| Spectral exposure | Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-nu"></ref> | joule per square metre per hertz | J⋅m−2⋅Hz−1 | M⋅T−1 | Radiant exposure of a surface per unit frequency or wavelength. The latter is commonly measured in J⋅m−2⋅nm−1. This is sometimes also called "spectral fluence". |
| Template:Math<ref group="{{#if:|{{{3}}}|nb}}" name="note-suffix-lambda"></ref> | joule per square metre, per metre | J/m3 | M⋅L−1⋅T−2 | ||
| See also: Template:Hlist | |||||
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