A microwave oven does not change the frequency of the power it receives from the electrical outlet. The frequency of the power supplied to most residential appliances, including microwave ovens, is typically 50 or 60 Hertz (Hz), depending on the region. In the United States and some other countries, the frequency is 60 Hz, while in many other countries, it is 50 Hz.
The power supplied to a microwave oven remains at this fixed frequency throughout the operation. The microwave oven uses the electrical power at the specified frequency to generate microwaves, which are a type of electromagnetic radiation, to cook or heat food.
Inside the microwave oven, there is a component called a magnetron. The magnetron converts electrical energy into electromagnetic waves with a frequency of around 2.45 Gigahertz (GHz). These microwaves are then directed into the cooking chamber, where they interact with water molecules present in the food.
When the microwaves encounter water molecules, they cause the water molecules to vibrate and generate heat. This heat is what cooks or heats the food. Since most food items contain water to some extent, microwave ovens are effective at heating a wide variety of foods quickly and efficiently.
It's important to note that the frequency conversion occurs within the microwave oven, not in the power supply. The electrical power supplied to the microwave oven remains at a constant frequency as determined by the electrical grid of the region.