In a microwave oven, microwaves are generated by a component called a magnetron. The magnetron produces high-frequency electromagnetic waves, commonly known as microwaves, with a wavelength of approximately 12 centimeters (4.7 inches).
When you place food inside the microwave and activate it, the microwaves emitted by the magnetron penetrate the food. These microwaves interact with the water molecules, fats, and sugars present in the food. The microwaves rapidly oscillate the water molecules, causing them to vibrate and generate heat through a process called dielectric heating. This heat then cooks or reheats the food.
Once the cooking process is complete and the microwave is turned off, the microwaves cease to be produced by the magnetron. They do not linger inside the oven or the food. Microwaves are a form of electromagnetic radiation, similar to radio waves or light waves. They travel at the speed of light, so when the microwave oven is turned off, the microwaves disperse into the surrounding environment.
The microwave oven is designed with a metal enclosure that prevents the microwaves from escaping and potentially causing harm to people nearby. The door of the microwave oven has a metal mesh or a conductive coating that reflects the microwaves back into the cooking chamber, preventing their leakage.
It's important to note that microwaves are non-ionizing radiation, which means they do not have enough energy to cause ionization or damage to DNA, as opposed to ionizing radiation like X-rays or gamma rays. Microwave ovens are considered safe for use as long as they are properly maintained, and the instructions and safety precautions provided by the manufacturer are followed.