microwaves do not have the capability to sense the size of a potato or any other food item directly. Instead, microwaves rely on the interaction between electromagnetic radiation and the water molecules present in the food to heat it.
When you place a potato or any other food item in a microwave oven and turn it on, the magnetron (the microwave's energy source) generates electromagnetic waves at a specific frequency, usually around 2.45 gigahertz. These microwaves are then directed into the cooking chamber, where they interact with the water molecules present in the food.
Water molecules are polar, which means they have a positive and negative end. The microwave's electromagnetic waves cause these water molecules to vibrate rapidly, generating heat through friction. This heat then cooks the food from the inside out, as the microwaves can penetrate several centimeters into the food.
The cooking time for a potato (or any other food) in a microwave is generally set by the user based on their knowledge of the size and weight of the food item. The microwave oven doesn't have any sensors to determine the size or weight of the potato. Instead, it heats the food based on the cooking time and power level selected by the user.
It's worth noting that newer microwave models may come with advanced features like sensors that can detect moisture levels or temperature to optimize cooking settings automatically. However, even with these sensors, they do not determine the size of the potato but rather adjust the cooking process based on the detected moisture or temperature changes in the food during the cooking process. These sensors help prevent overcooking or undercooking and can provide more even cooking results.