Lumen is amount of light emitted from light source.

According to Wikipedia, "If a light source emits one candela of luminous intensity into a solid angle of one steradian, the total luminous flux emitted into that solid angle is one lumen. Alternatively, an isotropic one-candela light source emits a total luminous flux of exactly 4π lumens. The lumen can be thought of casually as a measure of the total amount of visible light emitted." For example, a standard 100 Watt incandescent bulb emits about 1500 lumen.

Need return to FAQs category? Please click here LED FAQs or http://www.eosled.com/faqs/