In telecommunication, a conservation of radiance is a basic principle of optics, that no passive optical system can increase the quantity L /n2, where L is the radiance[?] of a beam and n is the local refractive index.
Note:"Conservation of radiance" was formerly called "conservation of brightness" or the "brightness theorem."
... 20.5% from 45 to 64, and 14.1% who are 65 years of age or older. The median age is 28 years. For every 100 females there are 82.8 males. For every 100 females age 18 and ...