X-rays are called electromagnetic waves because they are a form of electromagnetic radiation, just like visible light, radio waves, and microwaves. Electromagnetic radiation encompasses a broad range of wavelengths and frequencies, and X-rays fall within this spectrum.
Electromagnetic waves are composed of electric and magnetic fields that oscillate perpendicular to each other and propagate through space. They do not require a medium to travel and can travel through vacuum. The properties of electromagnetic waves, including X-rays, are governed by Maxwell's equations, which describe the behavior of electric and magnetic fields.
X-rays specifically are a high-energy form of electromagnetic radiation with shorter wavelengths and higher frequencies than visible light. They were first discovered by Wilhelm Conrad Roentgen in 1895 and named X-rays to indicate their unknown nature at the time. The "X" in X-rays signifies the unknown or X-factor. Later, it was understood that X-rays are a part of the electromagnetic spectrum.
X-rays have distinctive properties that make them useful in various applications, such as medical imaging, scientific research, and industrial testing. Due to their higher energy, X-rays can penetrate many materials, including body tissues, allowing for the visualization of internal structures and detection of abnormalities.