A good resource to learn about radio and electromagnetic waves, including their nature and physical properties, is a textbook on electromagnetics or a comprehensive online tutorial. Here are a few resources you can explore:
"Introduction to Electrodynamics" by David J. Griffiths: This textbook provides a thorough introduction to electromagnetism and covers the fundamentals of radio and electromagnetic waves. It explains the nature of electromagnetic fields and their propagation.
"Electromagnetics" by John D. Kraus and Daniel A. Fleisch: This textbook covers the principles of electromagnetism, including the concepts of electromagnetic waves, antennas, and wave propagation. It provides a solid foundation in understanding radio waves.
Khan Academy: Khan Academy offers a series of video tutorials on electromagnetism, including topics related to radio waves and electromagnetic waves. The tutorials provide clear explanations and visual representations to aid in understanding.
HyperPhysics (Georgia State University): HyperPhysics is an online resource that provides concise and well-organized information on various physics topics. The Electromagnetism section covers radio waves and electromagnetic waves, explaining their properties and characteristics.
Regarding the oscillating electric and magnetic fields, electromagnetic waves consist of mutually perpendicular oscillating electric and magnetic fields that are self-propagating through space. These fields are interconnected and support each other's existence. As the electric field changes its strength and direction, it generates a changing magnetic field, and vice versa. These oscillations occur perpendicular to the direction of wave propagation, forming a transverse wave.
The amplitude of a radio wave refers to the maximum value of the electric or magnetic field strength within the wave. Physically, the amplitude represents the maximum displacement or intensity of the electric or magnetic fields during each cycle of oscillation. In the case of radio waves, the amplitude determines the strength or power of the signal being transmitted. Higher amplitudes correspond to stronger signals, while lower amplitudes indicate weaker signals.
It's important to note that in modern digital communication systems, the amplitude of the radio wave is typically not used for transmitting information. Instead, information is encoded in the modulation of the wave, such as phase or frequency modulation. Amplitude modulation (AM) is still used in some applications, such as in amplitude modulation radio broadcasting.