In the field of physics, the Candela (often denoted by the symbol ‘cd’) can be defined as the unit of luminous intensity – a measure of the wavelength weighted power emitted by a source of light. As per the International System of Units (often abbreviated to SI), the Candela is a base unit that can be defined by taking the fixed value (in numerical terms) of the luminous efficacy of the monochromatic radiation having a frequency of 540 x 1012 Hertz. Alternately, it can be described as the luminous power corresponding to one unit solid angle that is emitted by a point source of light (in a given direction).
- The SI base unit for luminous intensity has Latin roots – the word ‘candela’ translates to ‘candle’ in the Latin language.
- It can be noted that the luminous intensity associated with the light emitted by a common wax candle is roughly equal to one candela.
