Question

a cfl bulb has an efficiency of 8.9% and a power of 22 w. how much light energy does the lightbulb produce in 1 second?

a. 20.0 j
b. 22.0 j
c. 1.96 j
d. 4.23 j

Explanation:

Step1: Calculate the total energy consumed

Power \(P=\frac{W}{t}\), so \(W = P\times t\). Given \(P = 22\space W\) and \(t = 1\space s\), then \(W_{total}=22\times1=22\space J\)

Step2: Calculate the light energy produced

Efficiency \(\eta=\frac{W_{light}}{W_{total}}\), so \(W_{light}=\eta\times W_{total}\). Given \(\eta = 8.9\%=0.089\) and \(W_{total} = 22\space J\), then \(W_{light}=0.089\times22 = 1.958\approx1.96\space J\)

Answer:

C. 1.96 J