The type of electromagnetic wave utilized in microwave ovens is microwaves. These waves have a specific frequency range that allows them to excite water molecules in food, leading to heat generation. As the microwaves penetrate food, they cause the water molecules to vibrate rapidly, creating heat through friction. This process results in efficient cooking and reheating of food. Microwaves are part of the broader electromagnetic spectrum, which includes radio waves, infrared radiation, visible light, ultraviolet rays, X-rays, and gamma rays.