The candela is the SI unit of luminous intensity. The candela is used to measure the visual intensity of light sources, like light bulbs or the bulbs in torches. It is the only SI base unit based on human perception
The Candela would be a fundamental unit defined as such constant value of the luminous effectiveness of monochromatic radiation with a frequency of .
The SI base unit for luminous intensity is derived from Latin, the term 'candela' corresponds to 'candle' throughout Latin.