The total electrical energy used by the toaster can be calculated using the formula:
Energy (in watt-seconds) = Power x Time
where power is measured in watts and time is measured in seconds.
In this case, the toaster is rated at 1200 watts and we want to calculate the energy used in 30 seconds. However, we need to convert the power from watts to watt-seconds by multiplying by the time.
So the total electrical energy used by the toaster for 30 seconds is:
Energy = Power x Time
= 1200 watts x 30 seconds
= 36,000 watt-seconds
We can also express this result in kilowatt-hours (kWh), which is a more common unit for measuring electrical energy consumption. To convert watt-seconds to kWh, we divide by the conversion factor 3,600,000 (the number of watt-seconds in one kWh):
Energy (in kWh) = Energy (in watt-seconds) / 3,600,000
= 36,000 / 3,600,000
= 0.01 kWh
Therefore, the toaster uses 36,000 watt-seconds or 0.01 kWh of electrical energy to operate for 30 seconds.