Question

A 4.0 W LED bulb produces 240 lumens. What is the efficacy of the bulb?

1. 1.7 lm/W
2. 60 lm/W
3. 236 lm/W
4. 244 lm/W

Answer 1

its B) 60

Step-by-step explanation:

Answer 2

Efficacy is the ratio of light output from a lamp or a bulb to the electric power it consumes and is measured in lumens per watt (LPW).
In this case; the power is 4 watt and the number of lumens is 240.
Efficacy = lumens/power
= 240/4
= 60 lm/W
Thus the efficacy of the bulb is 60 lm/W