In a certain city, electricity costs $0.13 per kW·h.
What is the annual cost for electricity to power a lamp-post for 7.50 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.

(a) 100.-watt bulb
(b) 25-watt bulb

The question is asking to compute the annual cost of electricity to power a lamp post for 7.5 hrs per day with the following power, and base on my calculation, the answers would be the following:
#1. 7,580,769.23
#2. 1,895,195.31
I hope you are satisfied with my answer and feel free to ask for more if you have questions and further clarifications.

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aristocles aristocles · Answer 2 · 2019-09-04T03:26:16+02:00

Answer:

Part a)

cost = $35.58

Part b)

cost = $8.89

Explanation:

Part a)

Annual cost of the incandescent light bulb

Power = 100 Watt

daily use = 7.5 hours

total use of one year

[tex]Energy = 100 \times 7.5 \times 365[/tex]

[tex]Energy = 273750 Wh[/tex]

[tex]Energy = 273.75 kWh[/tex]

cost of energy = $0.13 per kWh

so total cost of energy = $0.13 (273.75)

cost = $35.58

Part b)

25 watt fluorescent bulb

Power = 25 Watt

daily use = 7.5 hours

total use of one year

[tex]Energy = 25 \times 7.5 \times 365[/tex]

[tex]Energy = 68437.50 Wh[/tex]

[tex]Energy = 68.437 kWh[/tex]

cost of energy = $0.13 per kWh

so total cost of energy = $0.13 (68.437)

cost = $8.89