What is the expected lumenance value, in watts, of a 200 watt fluorescent lamp after three years?

120 watts represents a 40% reduction, which exceeds the typical lumen depreciation rate for fluorescent lamps at the three-year mark.

Fluorescent lamps experience lumen depreciation of approximately 30% over a three-year operational period due to phosphor degradation and electrode wear. Applying a 30% reduction to a 200-watt lamp's rated output yields an expected effective output of 140 watts (200 x 0.70 = 140), consistent with industry-standard lamp life and light loss factor calculations.

160 watts reflects only a 20% reduction, which underestimates the documented lumen depreciation for fluorescent lamps over a three-year period.

180 watts represents only a 10% reduction, which is too optimistic and does not reflect the actual phosphor and electrode degradation that occurs by year three.

200 watts assumes zero lumen depreciation, which is incorrect because all fluorescent lamps experience measurable light output reduction throughout their operational life.