well microwaves are on the light spectrum, but this article here says that they're radio waves, but light is a wave, so this makes sense.
A microwave oven uses microwaves to heat food. Microwaves are radio waves. In the case of microwave ovens, the commonly used radio wave frequency is
roughly 2,500 megahertz (2.5 gigahertz). Radio waves in this frequency range have an interesting property: they are absorbed by water, fats and
sugars. When they are absorbed they are converted directly into atomic motion - heat. Microwaves in this frequency range have another interesting
property: they are not absorbed by most plastics, glass or ceramics. Metal reflects microwaves, which is why metal pans do not work well in a
microwave oven.
(and Its a short read)
