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9/1/2018 11:59 PM A 66.2/100 20 of 24 University Science Books presented by Sapl

ID: 713862 • Letter: 9

Question

9/1/2018 11:59 PM A 66.2/100 20 of 24 University Science Books presented by Sapling Learning General Chemistry 4th Edition In a certain city, electricity costs $0.19 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 scent bulb that produces the same amount of light? Assume 1 year 365 days (a) 100-watt bulb (b) 25-watt bulb Number c) A typical incandescent bulb costs $0.89 and lasts for about a year; a costs about $3.49 and lasts for about 3 years. Is the O yes no Previcous G Ue& Viw Solution O Check Answer NextEx

Explanation / Answer

a)

Answer

$ 38.14

Explanation

1kW. h = 3.6MJ

Cost of 3.6MJ = $0.19

Total running time of bulb =( 5.50hr/1day) × 365day =2007.5hr = 7227000s

Power of bulb = 100watt = 100J/s

Total energy consumed per year = 100J/s × 7227000s = 722700000J

Cost of power per year =( $0.19/3600000J)×722700000J = $38.14

b)

Answer

$ 9.54

Explanation

power of bulb = 25 watt = 25J/s

Total energy consumed per year = 25J/s × 7227000s = 180675000J

Cost of power per year =($0.19/3600000J)×180675000J = $9.54

c)

Answer

yes

Explanation

Total cast of incandescent bulb = $0.89 + ( 1year × $38.14/year) = $39.03

cost per year for incandescent bulb = $39.03

Total cast of fluorescent lamp = $3.49 + ( 3year + $9.54/year) = $32.11

cost per year for florescent lamp = $32.11 /3 = $10.70

per year cost for flourescent lamp is lower than the per year cost incandescent lamp.

Therefore

additional cost of flourescent lamp justified