In 1895, German scientist Roentgen, while studying cathode rays experimentally, accidentally discovered the existence of some unknown invisible rays are called X-rays or Roentgen rays. X rays are nothing but electromagnetic waves or stream of photons having wavelength in the range of 0.1Å to 100Å.
Principle: When highly energetic cathode rays are suddenly stopped by a heavy metal of high melting point, X-rays are produced.
Characteristics of X Rays:
1. The positions of these peaks don’t depend on the applied accelerating voltage but depend upon the nature of the target material.
2. These X-rays occur in groups named as K, L series.