If the EM waves emitted by a cell phone and a microwave oven have similar frequencies, what does it mean that the waves emitted by the oven contain more energy? I believe that a microwave oven generates about 500 watts, whereas a cell phone generates only about 2 watts. What exactly does that mean? Since the wave frequencies are similar, does this mean that the oven produces waves with greater amplitude? I understand that the waves generated by the oven are amplified inside the oven itself, but I'm trying to understand what makes the waves themselves different to begin with.