A 1000 W bulb fitted with a reflector illuminates an area of 3 m x 3 m with an average illumination of 450 lux.
If the bulb has and efficiency of 9 lumens / watt the efficiency of the reflector is
A. 70 %.
B. 30 %.
C. 20 %.
D. 45 %.
Show Answer
Answer: D
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