IEVref:845-29-094ID:
Language:enStatus: Standard
Term: form factor, <between two surfaces>
Synonym1:
Synonym2:
Synonym3:
Symbol: f12
f21
Definition: quotient of the average radiant flux density or luminous flux density, Φ2/A2 (or Φ1/A1), received over surface S2 (or S1) from surface S1 (or S2) and the radiant exitance or luminous exitance, M1 (or M2), of surface S1 (or S2)

f 21 = Φ 2 A 2 M 1 = g A 2 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadAgadaWgaaWcbaGaaGOmaiaaigdaaeqaaOGaeyypa0ZaaSaaaeaa cqqHMoGrdaWgaaWcbaGaaGOmaaqabaaakeaacaWGbbWaaSbaaSqaai aaikdaaeqaaOGaamytamaaBaaaleaacaaIXaaabeaaaaGccqGH9aqp daWcaaqaaiaadEgaaeaacaWGbbWaaSbaaSqaaiaaikdaaeqaaaaaaa a@445F@

or

f 12 = Φ 1 A 1 M 2 = g A 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadAgadaWgaaWcbaGaaGymaiaaikdaaeqaaOGaeyypa0ZaaSaaaeaa cqqHMoGrdaWgaaWcbaGaaGymaaqabaaakeaacaWGbbWaaSbaaSqaai aaigdaaeqaaOGaamytamaaBaaaleaacaaIYaaabeaaaaGccqGH9aqp daWcaaqaaiaadEgaaeaacaWGbbWaaSbaaSqaaiaaigdaaeqaaaaaaa a@445D@

with

A 2 f 21 =g= A 1 f 12 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadgeadaWgaaWcbaGaaGOmaaqabaGccaWGMbWaaSbaaSqaaiaaikda caaIXaaabeaakiabg2da9iaadEgacqGH9aqpcaWGbbWaaSbaaSqaai aaigdaaeqaaOGaamOzamaaBaaaleaacaaIXaGaaGOmaaqabaaaaa@42A7@

where Φ2 (or Φ1) is the radiant flux or luminous flux received over surface S2 (or S1) from surface S1 (or S2), A2 (or A1) is the area of surface S2 (or S1) and g is the mutual exchange coefficient

Note 1 to entry: The form factor has unit one.

Note 2 to entry: This entry was numbered 845-09-73 in IEC 60050-845:1987.


Publication date:2020-12
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