When two electromagnetic waves of the same wavelength are placed half a wavelength apart from each other, they can interfere destructively, resulting in a cancellation of the waves. This phenomenon is known as destructive interference. However, it's important to note that the cancellation refers to the amplitude or intensity of the waves, not the actual energy associated with them.
Energy in electromagnetic waves is proportional to the square of the wave's amplitude. When the waves interfere destructively, their amplitudes add up negatively, causing the net amplitude to become zero. This means that at specific points where destructive interference occurs, the amplitude of the resultant wave becomes zero, indicating no energy at those points.
However, the energy of the individual waves does not disappear. It is redistributed or redistributed elsewhere. In the case of destructive interference, the energy is redistributed in such a way that the regions where the waves cancel out have lower energy compared to other regions. The energy that was initially present in those regions is essentially transferred or distributed to regions where constructive interference occurs, resulting in regions of higher energy.
In other words, the energy is conserved within the system, but its distribution changes due to the interference pattern. The total energy remains constant, but it is redistributed spatially within the system of interacting waves.