(power and energy) if electricity costs $0.09 per kilowatt hour, find the cost (in dollars) of running each of the following electrical devices six hours per day for 30 days:

a. a 60 watt incandescent light bulb
b. an led light bulb that emits the same light intensity as a 60 w incandescent light bulb, but uses 80 ma from a 120 v residential power wall outlet
c. a 1500 w electric space heater that runs continuously over the six-hour daily period

a) $0.97

b) $0.16

c) $24.30

Step-by-step explanation:

$0.09 per kilowatt hour = $0.09/kWh

6h/day 30 days = 180h

a) 60W*180h = 10800 Wh = 10.8kWh

10.8kWh * $0.09/kWh = $0.97

b) P = V*I

V = 120V

I = 80mA = 80/1000 = 0.08A

P = 120*0.08 = 9.6W

9.6W*180h = 1728 Wh = 1.728kWh

1.728kWh * $0.09/kWh = $0.16

c) 1500W*180h = 270000 Wh = 270kWh

270kWh * $0.09/kWh = $24.30

a. is correct

answer 1 : option "c"

answer 2 : option "d"

answer 3 : option "b"

answer 4 : option "d"

answer 5 : option "b"

answer 6 : option "a"

answer 7 : option "c"

answer 8 : option "d"

answer 9 : option "c"

answer 10 : option "d"

answer 11 : option "c"

answer 12 option "b"

answer 13 option "c"

answer 14 option "c"

answer 15 option "d"

answer 16 option "a"

answer 17 option "b"

answer 18 option "c"

answer 19 option "a"

answer 20 option "a"

answer 21 option "c"

d