Final answer:
The rice cooker uses 0.4 kWh of electrical energy. Hence the correct answer is option A
Step-by-step explanation:
To calculate the electrical energy used by the rice cooker, we can use the formula:
Energy (kWh) = Power (kW) x Time (hours)
In this case, the power of the rice cooker is 800 W, which is equal to 0.8 kW. The time it is switched on is 30 minutes, which is equal to 0.5 hours.
Plugging the values into the formula, we get:
Energy (kWh) = 0.8 kW x 0.5 hours = 0.4 kWh.
Therefore, the rice cooker uses 0.4 kWh of electrical energy.
Hence the correct answer is option A