These texts cover the topic of electromagnetic waves, detailing their nature as perpendicular oscillating electric and magnetic fields that propagate through space, even vacuum. They explain the origins of this theory through the work of Maxwell and Hertz, highlighting key characteristics like speed, frequency, wavelength, and amplitude. The sources also describe the different types of electromagnetic waves within the spectrum, ranging from radio waves to gamma rays, and discuss their various everyday applications and interactions with matter, often in the context of physics education and exam preparation.