In a certain city, electricity costs $0.13 per kW·h. What is the annual cost for electricity to power a lamp-post for 5.50 hours per day with (a) a 100.-watt incandescent light bulb (b) an energy efficient 25-watt fluorescent bulb that produces the same amount of light? Assume 1 year = 365 days.

Question

Gaige Beck

Chemistry

4 October, 20:51

In a certain city, electricity costs $0.13 per kW·h. What is the annual cost for electricity to power a lamp-post for 5.50 hours per day with (a) a 100.-watt incandescent light bulb (b) an energy efficient 25-watt fluorescent bulb that produces the same amount of light? Assume 1 year = 365 days.

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Answers (1)

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Kylie Underwood · Answer 1

We know power=work done/time taken

power*time = work

100watt=0.1kw

total work in a day = power * time

0.1*5.5=0.55kwh

for 1 year total. energy is 0.55*365=200.75kwh

cost is 200.75*0.13=26.0975dollars

for 25 watt it is 0.025*5.5*365*0.13=6.524375 dollars