Usuario:Rafstr/Radiancia

		Unit		Dimension	Notes
Name	Symbol​	Name	Symbol	Symbol
Radiant energy	Qe​	joule	J	M⋅L2⋅T −2	Energy of electromagnetic radiation.
Radiant energy density	we	joule per cubic metre	J/m3	M⋅L−1⋅T −2	Radiant energy per unit volume.
Radiant flux	Φe​	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	Φe,ν​	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.
	Φe,λ​	watt per metre	W/m	M⋅L⋅T −3
Radiant intensity	Ie,Ω​	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	Ie,Ω,ν​	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.
	Ie,Ω,λ​	watt per steradian per metre	W⋅sr−1⋅m−1	M⋅L⋅T −3
Radiance	Le,Ω​	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	Le,Ω,ν​	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".
	Le,Ω,λ​	watt per steradian per square metre, per metre	W⋅sr−1⋅m−3	M⋅L−1⋅T −3
Irradiance Flux density	Ee​	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	Ee,ν​	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 (1 Jy = 10−26 W⋅m−2⋅Hz−1) and solar flux unit (1 sfu = 10−22 W⋅m−2⋅Hz−1 = 104 Jy).
	Ee,λ​	watt per square metre, per metre	W/m3	M⋅L−1⋅T −3
Radiosity	Je​	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	Je,ν​	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".
	Je,λ​	watt per square metre, per metre	W/m3	M⋅L−1⋅T −3
Radiant exitance	Me​	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	Me,ν​	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".
	Me,λ​	watt per square metre, per metre	W/m3	M⋅L−1⋅T −3
Radiant exposure	He	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	He,ν​	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".
	He,λ​	joule per square metre, per metre	J/m3	M⋅L−1⋅T −2