A microwave oven has a power requirement of 1256 W. A frozen dinner requires 4.0 min to heat on full power.
(a) How much electrical energy (in kWh) is used?
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1256 W = 1.256 kW
4min/60min = .067 hour
1.256 * .067 = ?
To calculate the electrical energy used by the microwave oven, we need to multiply the power requirement of the microwave by the time it takes to heat the frozen dinner.
First, let's convert the power requirement from watts (W) to kilowatts (kW):
1 W = 0.001 kW
So, the power requirement is 1256 W = 1.256 kW.
Now, let's convert the time from minutes to hours:
1 min = 0.0167 hours
So, the heating time is 4.0 min = 0.067 hours.
Next, we can calculate the electrical energy used:
Electrical energy = Power requirement × Time
Electrical energy = 1.256 kW × 0.067 hours
Electrical energy = 0.084152 kWh
Therefore, the microwave oven uses approximately 0.084152 kWh of electrical energy.