Light & Optics

A light of 100 candlepower that shines evenly in all directions gives about 1,257 lumens. Quick answer: Multiply the candlepower by 4 pi, which is about 12.566. For example, 100 candlepower is 1,256.64 lm, 1 candlepower is 12.566 lm and 500 candlepower is 6,283.19 lm. The candlepower to lumens formula Lumens equal candlepower times 4…

A bulb that gives 800 lumens from 10 watts has an efficacy of 80 lumens per watt. Quick answer: Divide the lumens by the watts. For example, 800 lm from 10 W is 80 lm/W, 800 lm from 60 W is 13.333 lm/W and 1,600 lm from 12 W is 133.33 lm/W. The lumens per…