No, microwaves do not heat up food by absorbing light energy from the sun. Microwaves work on an entirely different principle called "microwave radiation."
Microwaves are a form of electromagnetic radiation, just like visible light, radio waves, and X-rays, but they operate at a different frequency. The microwaves generated by the microwave oven are in the range of 2.4 to 2.45 gigahertz, which is a much lower frequency than visible light.
Here's how microwave ovens work:
Microwave Generation: A microwave oven contains a magnetron, a device that converts electrical energy into microwave radiation.
Microwaves in the Oven: The magnetron emits microwaves into the cooking chamber of the microwave oven.
Interaction with Food: When microwaves pass through the food, they cause water molecules to vibrate rapidly due to their dipolar nature (having a positive and negative end). This vibration generates heat as the water molecules collide with other molecules in the food, causing them to move and generate heat as well.
Uniform Heating: The microwaves are designed to be absorbed primarily by water molecules, which are present in most foods. This uniform absorption of microwaves results in even and rapid heating of the food.
In summary, microwaves use microwave radiation to heat food by exciting water molecules within the food. The heat is generated internally, and it is not related to absorbing light energy from the sun. That's why microwave ovens can cook food quickly without the need for external heating sources like a stovetop or an open flame.