>> 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.
The unit of measuring the brightness-or to use the precise scientific terminology, illuminance-in SI system of measurement is lux or lumen per square meter.Illuminance is measured in foot candles. One foot-candle is equal to 10.76 lux. Please note that lumen is the measure of total light emitted by a source of light.he total amount of visible light is measured in units of lumens. How bright it appears when it falls on a surface area is illuminance. When the same luminous flux falls over a larger area it will appear to be less bright. 1 lx = 1 lm/m^2 which in terms of the basic SI units is 1 cd*sr*m^-2.