The wavelength range of X-rays is approximately:
0.01 nanometers (nm) to 10 nanometers (nm)
or in meters: 1 × 10⁻¹¹ m to 1 × 10⁻⁸ m
This range corresponds to frequencies from about 3 × 10¹⁶ Hz to 3 × 10¹⁹ Hz, and photon energies from roughly 0.1 keV to 100 keV.
For classification:
- Soft X-rays → longer wavelengths (0.1–10 nm), lower energy.
- Hard X-rays → shorter wavelengths (0.01–0.1 nm), higher energy, more penetrating.