Bril (unit) - Wikipedia
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The bril is an old, non-SI, unit of luminance. The SI unit of luminance is the candela per square metre.
cd/m2 (SI unit) ≡ nit ≡ lm/m2/sr |
stilb (sb) (CGS unit) ≡ cd/cm2 |
apostilb (asb) ≡ blondel |
bril | skot (sk) | lambert (L) | foot-lambert (fL) = 1 ⁄ π cd/ft2 | |||
---|---|---|---|---|---|---|---|---|---|
1 cd/m2 | = | 1 | 10−4 | π ≈ 3.142 |
107 π ≈ 3.142×107 |
103 π ≈ 3.142×103 |
10−4 π ≈ 3.142×10−4 |
0.30482 π ≈ 0.2919 | |
1 sb | = | 104 | 1 | 104 π ≈ 3.142×104 |
1011 π ≈ 3.142×1011 |
107 π ≈ 3.142×107 |
π ≈ 3.142 |
30.482 π ≈ 2919 | |
1 asb | = | 1 ⁄ π ≈ 0.3183 |
10−4 ⁄ π ≈ 3.183×10−5 |
1 | 107 | 103 | 10−4 | 0.30482 ≈ 0.09290 | |
1 bril | = | 10−7 ⁄ π ≈ 3.183×10−8 |
10−11 ⁄ π ≈ 3.183×10−12 |
10−7 | 1 | 10−4 | 10−11 | 0.30482×10−7 ≈ 9.290×10−9 | |
1 sk | = | 10−3 ⁄ π ≈ 3.183×10−4 |
10−7 ⁄ π ≈ 3.183×10−8 |
10−3 | 104 | 1 | 10−7 | 0.30482×10−3 ≈ 9.290×10−5 | |
1 L | = | 104 ⁄ π ≈ 3183 |
1 ⁄ π ≈ 0.3183 |
104 | 1011 | 107 | 1 | 0.30482×104 ≈ 929.0 | |
1 fL | = | 1 ⁄ 0.30482 ⁄ π ≈ 3.426 |
1 ⁄ 30.482 ⁄ π ≈ 3.426×10−4 |
1 ⁄ 0.30482 ≈ 10.76 |
107 ⁄ 0.30482 ≈ 1.076×108 |
103 ⁄ 0.30482 ≈ 1.076×104 |
10−4 ⁄ 0.30482 ≈ 1.076×10−3 |
1 |
- ^ The symbols in this column denote dimensions; "L", "T" and "J" are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
- ^ Standards organizations recommend that photometric quantities be denoted with a subscript "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
- ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.