Answer:
There is a whole bunch of energy trans formation taking place, layers and layers in fact:
First an elecric motor transforms electricity into kinetic energy and thermal energy.That motor turns a magnatron converting producing a specific band width of microwaves particularly well tuned to heating water molecules.
Those microwaves are doing all sorts of stuff:
Most are bouncing off the reflective surface of the fan blades attached to the motor/magnatron assembly and walls of the appliance but some of them are absorbed increasing the energy level and heat of the molecules of those surfaces (kinetic and thermal energy).
Then most of those bounced microwaves hit the food or food vessel the food is in. Some of those photons are absorbed being transferred to kinetic and thermal radiation at a new wave length and some go on their merry way.
Some of those microwaves pass by water molecules which, because water molecules have a polar charge, start spinning, causing transfer of em energy to kinetic energy and then kinetic energy to thermal energy. So again you get kinetic and thermal effects.
What give microwave cooking its unique characteristcs is the interplay between mucrowaves and water in the food. Microwaves are very, very efficient at heating water. So when you microwave food you are effectively steaming the food in its own juices.
Explanation:
