A Heureka a day..
March 28, 2008I think the problem with any kind of institutional education is that when you’re being taught something of a great intellectual value and you’re some 20 years of age and have NO IDEA whatsoever how to put this into practice or whatever connection it might have with Real Life, then you just listen and nod your head and forget about the whole thing. This is how we miss all the great chances to become smart in the University.
I eventually realized what luminous flux has to do with luminous intensity. It’s taken me five years to understand this and I feel stupid for saying this. Freshman knowledge, I know.
The luminous flux (measured in lumens) is all the visible light coming out of the source, any direction, any how, any way. When you look at the light from a fixed angle and take all the light in the area of one steradian, you will get the luminous intensity in candelas. In that direction. And reversed, the luminous flux is the intensity*steradians, suggesting that the intensity is even in all directions.
It took me half an hour to get this simple connection, a step closer to understanding luminous efficacy (lm/W) which shows us how many lumens you get from one watt of radiant flux (emitted energy/seconds) of a light source.
You are more than welcome to correct me if I’m still wrong about this.
[...] calculate lumens if you have the candelas given. I learned the thing myself only this spring (see earlier post from march) but it still feels good to be the smart one for change. It doesn’t matter that I cannot do [...]