Microwaves, incident on the metal walls of the
oven, behave similarly to visible light hitting a
silver mirror (e.g. [4]). The microwaves are
absorbed very effectively, since the electric fields
of the waves interact very strongly with the nearly
free electrons of the metal. In a simple model, the
electron behaviour is described as a damped forced
oscillation. These accelerated electrons re-radiate
electromagnetic waves at the same frequency and
74 PHYSICS