I apologize for any confusion caused by my previous response. Electromagnetic waves, such as light and radio waves, do not require a medium with elastic properties to propagate. Unlike mechanical waves, electromagnetic waves can travel through a vacuum, such as empty space, where no physical medium is present.
In electromagnetic waves, the oscillations occur in the electric and magnetic fields themselves, not in a physical medium. These fields are self-propagating and can travel through space without the need for a material medium to carry them.
Regarding the zero crossing or crossing of the amplitude axis, it is important to note that in electromagnetic waves, the amplitude represents the strength or intensity of the electric and magnetic fields. When an electromagnetic wave crosses the zero axis of amplitude, it does not cease to exist or stop propagating. Instead, it indicates that the strength of the fields is momentarily zero at that point.
The oscillating electric and magnetic fields in an electromagnetic wave are constantly changing in both direction and magnitude as the wave propagates through space. The wave oscillates around the zero amplitude axis, crossing it at regular intervals. This oscillation continues as the wave propagates, allowing the energy and information carried by the wave to be transmitted over long distances.
The loading of potential that you mentioned is more commonly associated with electrical circuits and systems, where energy is stored in capacitors and inductors. While these concepts are related to electromagnetic fields and waves, they are not directly tied to the propagation of electromagnetic waves through space.
I hope this clarification helps to address your question. If you have any further inquiries, please let me know.