>> 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.
In fact, the true brightness of Polaris is ten thousand Suns. When stating the true brightness, or luminosity, of stars, it is convenient to compare them with the luminosity of our own Sun. Our sun shines with a power output of 4 x 1026 Watts; for convenience, we say that this amount of power equals one Sun. A star that has only half the power output of the Sun is said to have a luminosity of 1/2. Another measure of a stars brightness is called its magnitude. The larger the number, the fainter the star. The brightest stars are about magnitude zero, and the faintest stars that can be seen with the naked eye are about magnitude 5.