Definition and basic electromagnetic properties

Summary

X-rays are a form of high-energy electromagnetic radiation with wavelengths shorter than ultraviolet light and longer than gamma rays. They typically span wavelengths from about 10 nanometers to 10 picometers, corresponding to photon frequencies roughly from 30 petahertz to 30 exahertz and photon energies from about 100 eV to 100 keV. X-rays were discovered in 1895 by Wilhelm Conrad Röntgen, who named them “X-radiation” to indicate an unknown type of radiation at the time. Electromagnetically, X-rays are characterized by their ability to penetrate many materials, including construction materials and biological tissue, which is why they are widely used in imaging and diagnostics. However, because X-rays are ionizing radiation, exposure can be hazardous to health, potentially causing DNA damage, cancer, and at higher intensities burns and radiation sickness. As a result, their generation and use are strictly controlled by public health authorities.

Key Points

• 1

  X-rays are high-energy electromagnetic radiation with wavelengths between ultraviolet and gamma rays.

• 2

  Typical X-ray photon energies range from about 100 eV to 100 keV, with corresponding frequency and wavelength ranges.

• 3

  X-rays can penetrate many substances, enabling medical imaging and materials analysis.

• 4

  X-rays are ionizing radiation, so exposure can be harmful and is regulated for safety.