Microwave ovens heat food primarily by which heat transfer mechanism?

• A. Conduction
• B. Convection
• C. Radiation
• D. Induction

Answer: (C)

Microwave ovens heat food primarily through radiation. They emit microwave electromagnetic waves that penetrate the food and cause polar molecules, especially water, to rotate rapidly as the field oscillates. This molecular motion converts the energy of the waves directly into heat inside the food, so heating happens without needing a hot oven surface. Conduction would require heat to transfer through direct contact from a hot area, and convection would rely on moving air or liquid to carry heat—neither is how the energy is delivered in a microwave. Induction heats metals with magnetic fields, which isn’t how food is heated here. So the main mechanism is radiation.