Lumen and brightness are unconnected.
Lumens are an imaginary measure of the amount of light (equivalent to a weight of apples for instance). A lamp will be said to emit X lumens.
Lumen figures are calculated from the amount of energy at any particular wavelength and then applying a correction to allow for the sensitivity of the human eye (which is greatest in the red-orange). Different correction figures are applicable for the two different types of human sight - that in high and low level illumination - photopic and scotopic respectively. Hence any light source will have both photopic and scotopic lumen figures. Photopic would be applicable to household or office lighting, scotopic to street lighting, for instance.
Different corrections are also known for other organisms, other than man, most importantly for plants, where plant lumens are a measure of the effect of any light-source on photosynthesis.
AnswerIn simple terms, the lumen is the photometry-equivalent of the watt. In other words, it defines the rate at which a source emits 'visible light' energy (as opposed to the watt, a radiometry unit, which defines the rate at which the same source emits allradiant energy (including visible light). Lumens are NOT used to measure 'brightness', or more accurately, luminous intensity (candelas) or luminance (candelas per square metre).Note that the 'watt', described above, is used to measure the output from a light source, not its input.
Radiometry describes the measurement of electromagnetic energy across a very broad spectrum. Photometry describes the measurement of just the 'visible light' part of the electromagnetic energy spectrum, as perceived by the human eye.
yes sometimes
Your Geography teacher, as far as you are concerned
Usually (all the time as far as we're concerned.
No. It is too small and too far away to be seen with the naked eye, despite its relative brightness when observed by telescopes.
Introduced species that are relatively new and untested can lead to economic losses as far as the mass production is concerned.
That all depends on what you are referring to as far as meaning is concerned. Please see the related link below for more.
It depends on the galaxy and how far you are from it
If a star IS very bright but LOOKS fairly dim, it must be far away.
As far as the theatre is concerned André is a play, a tragedy, written by playwright William Dunlap in 1798.
How dense it is, and how far away it is.
Your gums
As far as I'm concerned no!
The observer.
Not as far as I'm concerned.
As far as Arabs are concerned, horse-racing is the national sport
yes sometimes
As far as emotional feelings are concerned, a feeling of joy and satisfaction specific to the profession. For temperamental traits, meaning moody or irritable, non whatsoever