Lumen
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Définition
L'unité dérivée SI de flux lumineux, mesurant la quantité totale de lumière visible émise par une source par seconde (1 lm = 1 cd·sr).
Explication
A 60-watt incandescent bulb emits about 800 lumens; an equivalent LED uses only 8–10 watts for the same output. A candle produces roughly 12–13 lumens. Unlike watts (which measure power input), lumens measure actual light output — making them the correct metric for comparing bulb brightness across different technologies.
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RELATED TERMS
Mètre
L'unité SI de base de longueur, définie comme la distance parcourue par la lumière en 1/299 792 458 de seconde.
Kilogramme
L'unité SI de base de masse, définie par la constante de Planck.
Seconde
L'unité SI de base du temps, définie par les transitions de l'atome de césium-133.
Kelvin
L'unité SI de base de température thermodynamique, dont l'origine est le zéro absolu.
Ampère
L'unité SI de base du courant électrique.