The luminous intensity of a light source is the power of light. It is defined in a given direction and is measured in candela, cd.The candela is one of the seven base units of the SI system and specifies the luminous intensity in one specific angle from a light source. But it doesn’t indicate anything about the total amount of light being radiated from the light source.
The scientific definition of the candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10e12 Hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.
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