Which of the following best describes X-rays?

X-rays are a form of electromagnetic radiation, which places them within the electromagnetic spectrum alongside other forms such as visible light, ultraviolet light, and gamma rays. Electromagnetic radiation consists of waves of electric and magnetic fields that oscillate perpendicular to each other and to the direction of wave propagation. These waves do not require a medium to travel through, allowing them to propagate through a vacuum, which is a key characteristic of all electromagnetic waves, including X-rays.

X-rays have wavelengths ranging from about 0.01 to 10 nanometers, which is much shorter than wavelengths of visible light. This short wavelength gives X-rays their penetrating power, which allows them to pass through many materials, including human tissue. This property makes them invaluable for medical imaging and various scientific applications.

Sound waves, visible light, and mechanical waves do not fit the definition of X-rays. Sound waves are mechanical waves that require a medium, such as air or water, to travel, while visible light is just a small part of the electromagnetic spectrum that humans can perceive. Hence, the characterization of X-rays as electromagnetic radiation is accurate and encompasses their fundamental properties, making this the best description.