At what point do electric and magnetic fields on an antenna reach their maximum intensity?

The correct answer is that electric and magnetic fields on an antenna reach their maximum intensity when they are in phase. This is because when the electric field (E-field) and the magnetic field (H-field) are in phase with each other, their peaks occur simultaneously, resulting in constructive interference. This condition maximizes the intensity of the radiated electromagnetic wave.

In radio frequency applications, an antenna emits energy by converting electric currents into electromagnetic waves. The in-phase relationship between the electric and magnetic fields indicates that the energy is efficiently radiated away from the antenna. When the fields are not in phase, their combination can lead to destructive interference, reducing the overall intensity of the wave.

The choice regarding a quarter cycle apart refers to a phase difference that does not allow for the optimal arrangement of fields for maximum intensity. The equilibrium point would imply that the fields are not oscillating but are static, which does not correspond to radiated energy. The reference to maximum voltage does not directly relate to the phase relationship of the electric and magnetic fields, as maximum voltage does not guarantee that the fields are optimally aligned for maximum intensity. Thus, the phase alignment of the two fields is critical for achieving the highest intensity in electromagnetic wave propagation.