What is Candel?

Candela is a measurement of light intensity and is used in the international standard measurement system (SI). Historically, Candel was roughly equal to the intensity of light issued by a conventional candle. He came technically to define himself as an intensity in a given direction of the source, which publishes the monochromatic radiation of the frequency of 540 x 10 ^{12 Hertz and which has a radiant intensity in the same direction 1/683 watts on Steradian. The light measured at 120 Candele is roughly the same as the light emitted by a 100 watt bulb. During the 19th century, each country had its own level of light, and most of them were very difficult with accuracy. At the beginning of the 20th century, groups of nations began to adopt new standards, such as an international candle, which was based on a single type of lamp and were more consistent. In the end, it was decided at the age of 30 that a more accurate definition is needed.}

initially Candela was defined as a light emission of placian rAdiator, type of blackbody, freezing platinum, 3,223.4 degrees Fahrenheit (1,773 degrees Celsius). This correlated roughly with the light emitted by a typical candle, which makes it a suitable measure. At the end of the 1970s, experimental difficulties in creating a Plackian radiator at such high temperatures caused the current definition of Candel to less than desired. Dusts in radiometry allowed scientists to have a more specific definition, so the definition was accepted.

One of the reasons why Watt was not initially tied to Candel is the differences in the eye in vision of different wavelengths of light. The human eye is less attentive blue and red light, so more WPOSDOVOní is needed to create the same result in the brain as in yellow or green light. Therefore, the definition of Candel is defined as a very specific Hertz, which is not achieved in the actual common lighting. Some people for this reason criticize the modern definition of Candely and claim to have removed any customEje reasonable understanding of Candel as real light emissions.

The reason why the modern definition of Candela includes the phrase "1/683 watts per sheradian" is to be in harmony with the previous definition and avoid any confusion in comparing a modern unit with a historic Candel. In this context, the stense of the cone is the light, as it is based on the source, so that it would light up 1 square meter inner ball with a radius of 1 meter.