X-radiation (composed of X-rays) is a form of electromagnetic radiation. Electromagnetic radiation (EM radiation or EMR) is a form of radiant energy released by certain electromagnetic processes. Visible light is one type of electromagnetic radiation, other familiar forms are invisible electromagnetic radiations such as X-rays and radio waves.
Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 pentahertz to 30 exahertz (3×1016 Hz to 3×1019 Hz) and energies in the range 100 eV to 100 keV.X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays.
In many languages, X-radiation is referred to with terms meaning Röntgen radiation, after Wilhelm Röntgen, who is usually credited as its discoverer, and who had named it X-radiation to signify an unknown type of radiation.
The x-ray tube consists of an emitter (either a filament or a cathode), which emits electrons into a vacuum and an anode to accelerate the electrons. This establishes a flow of electrons through the tube.These electrons are referred to as a beam. The cathode is in the form of a filament which emits electrons when heated. The anode is made of copper and also carries the target.
A high p.d between the anode and the cathode is maintained by an external high-voltage source. A battery that supplies high current is used to heat the cathode filament, which in many cases is made of tungsten. The cathode is in the form of a coil to provide high resistance to the passing current.
Production of X-rays
The electrons from the filament experience the p. d and accelerated towards the anode. When they hit the anode, they are stopped and thereby transfer their energy to the electrons of the anode material. This gives rise to x-rays. It is only a very small percentage of their energy that is converted to x-rays, with the rest of it being transformed to heat.