A microwave oven has a power requirement of 1235 W. A frozen dinner requires 6.0 min to heat on full power.
(a) How much electrical energy (in kWh) is used?
b) If the cost of electricity is 12 cents per kWh, how much does it cost to heat the dinner?
I have answered this already, somewhere else.
To calculate the electrical energy used by the microwave oven and the cost to heat the dinner, we need to follow these steps:
(a) Calculating Electrical Energy Used:
Step 1: Convert the power requirement of the microwave oven from watts (W) to kilowatts (kW):
Power (in kW) = Power (in W) / 1000
= 1235 W / 1000
= 1.235 kW
Step 2: Calculate the energy consumed by the microwave oven in kilowatt-hours (kWh):
Energy (in kWh) = Power (in kW) x Time (in hours)
= 1.235 kW x (6.0 min / 60 min)
= 1.235 kW x 0.1 hours
= 0.1235 kWh
Therefore, the electrical energy used by the microwave oven is 0.1235 kWh.
(b) Calculating the Cost to Heat the Dinner:
Step 3: Multiply the energy consumed by the microwave oven by the cost of electricity per kilowatt-hour:
Cost = Energy (in kWh) x Cost per kWh
= 0.1235 kWh x $0.12/kWh
= $0.01482
Therefore, it costs approximately $0.01482 to heat the dinner.