When she went away for the weekend, Celia left her TV on by mistake. The TV has a power rating of 200.0 W. She was away from 6 p.m. on Friday night until 9 p.m. on Sunday. How much energy did leaving the TV on use? Give your answer in kWh.
a) When she went away for the weekend, Celia left her TV on by mistake. The TV has a power rating of 200.0 W. She was away from 6 p.m. on Friday night until 9 p.m. on Sunday. How much energy did leaving the TV on use? Give your answer in kWh.
b) If electricity costs 11.3 ¢per kWh, find out how much leaving the TV on costs her.
I attached my answer below. I am just wondering if the time is 51h becasue it is 6:00pm on Friday to 9:00pm on Sunday or if it is 3h.
My Answer:
a) P=200.0W/1000kW=0.2kW
Δt=51h
ΔE= ?
ΔE=PΔt
=(0.2kW)(51h)
=10.2kWh
Therefore, leaving the TV on used 10.2kWh of energy.
b) ΔE=10.2kWh
rate=11.3¢/kWh
Cost= ?
Cost=(ΔE)(rate)
=(10.2kWh)(11.3¢/kWh)
=115.26¢
=$1.15
Therefore, leaving the TV on cost $1.15.
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