The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency $540 \times 10^{12}$ hertz and that has a radiant intensity in that direction of $1/{{683}}$ watt per steradian.
| Unit | candela |
|---|---|
| Symbol | cd |
| Quantity | luminous intensity |
| Defining Constant | luminous efficacy |
| Defining Resolution |
CGPM Resolution 3 (1979) |
| Unit Type | SI base unit |
