X-RAYS
X-rays are types of electromagnetic radiation probably most well-known for their ability to see through a person's skin and reveal images of the bones beneath it.
X-rays were first observed and documented in 1895 by Wilhelm Conrad Roentgen, a German scientist who discovered them by accident! The first known x-ray is actually that of Roentgen’s wife’s hand! Roentgen called this newfound radiation "X" to indicate it was an unknown type of radiation.
We usually talk about x-rays in terms of their energy rather than wavelength. This is mostly because x-
rays have very small wavelengths - 10 billion times smaller than a meter - not much bigger than the size of an atom! When talking about x-rays, the unit of energy utilized is the electron volt (eV), i.e. the energy of a single photon.
Photon energy is inversely proportional to the wavelength.
A smaller wavelength corresponds to a higher energy according to the equation E= h c/λ. ("E" is Energy; "h" is Planck's constant; "c" is the speed of light; "λ" is wavelength).
Photon energy is thus directly proportional to the electromagnetic frequency. The higher the frequency, the higher the photon energy.
Most x-rays have a wavelength ranging from 10 to 0.01 nanometers, corresponding to energies in the range 100 eV to 100,000 eV.
X-rays are classified as either hard or soft. X-rays with photon energies above 10,000 eV are called
hard x-rays, while those with energies below 10,000 eV are called soft x-rays.