హోమ్ ❯ అన్నీ నిర్వచనాలు ❯ యూనిట్ ❯ కాండెలా (సిడి) యూనిట్ నిర్వచనం

కాండెలా (సిడి) యూనిట్ నిర్వచనం

The candela is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. The candela is represented by the symbol cd.

Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the luminosity function. This is the model of the sensitivity of the human eye to different wavelengths, standardized by the CIE and ISO.

A common wax candle emits light with a luminous intensity of approximately one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured.

The word candela is Latin for candle. The old term "candle" is still sometimes used, as in foot-candle and the more modern definition of candlepower.