Package javax.measure.quantity
Interface LuminousIntensity
- All Superinterfaces:
Quantity<LuminousIntensity>
Luminous flux density per solid angle as measured in a given direction relative to the emitting source.
The metric system unit for this quantity is "cd" (candela).
The candela, symbol cd, is the SI unit of luminous intensity in a given direction. It is
defined by taking the fixed numerical value of the luminous efficacy of
monochromatic radiation of frequency 540 × 10¹² Hz, Kcd, to be 683 when expressed
in the unit lm W−1, which is equal to cd sr W⁻¹, or cd sr kg⁻¹ m⁻² s³, where the kilogram,
metre and second are defined in terms of h, c and ∆νCs.
This definition implies the exact relation Kcd = 683 cd sr kg⁻¹ m⁻² s³ for monochromatic
radiation of frequency ν = 540 × 10¹² Hz. Inverting this relation gives an exact expression
for the candela in terms of the defining constants Kcd, h and ∆νCs:
1 cd = (Kcd / 683) kg m² s⁻³ sr⁻¹
- API Note:
- SI Base Unit
- Since:
- 1.0
- Version:
- 2.1
- Author:
- Jean-Marie Dautelle, Werner Keil, Thodoris Bais
- See Also:
-
Nested Class Summary
Nested classes/interfaces inherited from interface javax.measure.Quantity
Quantity.Scale -
Method Summary