Final answer:
The microwave oven uses 90,000 joules of energy to heat the bowl of soup.
Step-by-step explanation:
To calculate the amount of energy used by the microwave oven, we can use the formula W = Pt, where W is the energy in joules, P is the power in watts, and t is the time in seconds.
In this case, the power of the microwave oven is 1,000 W and the time it takes to heat the soup is 90 s. Plugging these values into the formula, we have W = 1,000 W * 90 s = 90,000 J.
Therefore, the microwave oven uses 90,000 joules of energy to heat the bowl of soup.