I explain it better. If we bring an electron from higher to lower energy level, the energy gap will be emitted as electromagnetic wave, because of the conservation of energy. When the same situation applies for a physical body, for example letting if falling down from some height, what does it...
As required I introduce myself here. My name is Giuseppe, I come from Italy but I'm doing my studies in Germany as electrical and electronic engineer (Bachelor now). I hope to contribute somehow to this beautiful community. See you around!