I do not understand the full theory behind destructive interference. Hence I need helps: 1. The topic on destructive (and constructive) interference was always discussed on light and sound wave. Will this theory applicable on other radiation such as gamma? 2. During two wavelenghts met at a point with completely opposite phase, does the cancellation occur at that point with loss of energy? If so, how does the energy balance? does it still obey the energy conversation? if so, can provide some explanation on this? Thank you. Looking forward for some good discussion and explanation. Regards.