Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Problem:Passage: Electromagnetic waves may also be absorbed by matter and converted to other forms of energy. Microwaves are a familiar example. When microwaves strike food in a microwave oven, they are absorbed and converted to thermal energy, which heats the food. Answer: thermal energy
Solution:
Microwaves are converted into what kind of energy in a microwave oven?