alleryStart learning →A 1200-W toaster runs for 1 minute to make a slice of toast. How much electrical energy does that use?
A0.200 kWh
B1.20 kWh
C0.020 kWh
D0.72 kWh
Answer & Solution
Correct answer: C. 0.020 kWh
1. Energy used is power times time: E = Pt.
2. Convert the power to kilowatts: 1200 W = 1.20 kW.
3. Convert the time to hours: 1 minute = 1/60 h.
4. Multiply: E = 1.20 kW x 1/60 h = 0.020 kWh.
5. 1.20 kWh is the trap of charging a full hour of toasting for a one-minute job.
_Source: OpenStax College Physics (CC BY 4.0), Ch 20 "Electric Current, Resistance, and Ohm's Law", section 20.4 Electric Power and Energy_
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