>> Your prof was correct. Semantic domains, etymology, and all those >> little tidbits of trivia are interesting- but not useful in the final >> analysis because words gain meaning only from context. >[....] >> To isolate a word and assign it meaning is futile. >[....] > >There is more context to the text than the words proximate to >the text.
When looking at brightness specifications of LEDs, the most common specs available are luminous intensity (usually measured in units of candelas or millicandelas) and viewing angle (measured in degrees). The brightness of 1 candela is roughly around the same brightness as a common candle. A millicandela, or mcd, is 1000 times less bright than a candela, hence the prefix milli-. 1000 millicandelas = 1 candela. Since light is not always evenly dispersed, the viewing angle of a light source is very important.
Lumen is the SI unit of the luminous flux, which is a measure of the total amount of visible light emitted by a source. It is the perceived power of the light from a source.umen and Lux are two photometric units in the SI system of units. They are closely related to each other and, in simple language, measure how bright a light source appears in two different contexts. These measurements are important in light sources and other cases where the intensity of the light plays a role.