The electromagnetic (EM) wave energy is a significant part of the different purposes in the science, technical and engineering sectors. The phase difference between electric and magnetic fields holds important roles to give clear conception of (i) the EM wave energy and (ii) the action process of light-electron interactions. Most of the researchers think that the phase difference between electric and magnetic fields of the EM waves is 0°. In this work, we have discussed in detail about the phase difference between the fields. We have shown that the phase difference between the fields is 90° for all types of EM wave radiations in the both forms i.e. descriptive and mathematical. The electric field is the driver of the EM wave power. The source of the EM wave makes a sinusoidal electric field continuously then the changing electric field makes a magnetic field instantly in all paths of its propagation, so the magnetic field is sinusoidal also with a delay phase. The simulation of this research work shows that the radiated energy density is sinusoidal and continuous. The research work may help to increase the applications of the EM radiations.