ABSTRACT
X-rays refer to the electromagnetic radiations that have a wavelength range of 10-3 nm to 10 nm. X-rays with wavelengths below 0.10.2 nm are called hard X-rays, while those with longer wavelength are called soft X-rays. This chapter deals with principle and applications of X-ray diffraction and general properties of electromagnetic waves. Electromagnetic wave is a transverse wave propagating with oscillating electric and magnetic fields. Electromagnetic wave is characterized by its wavelength or frequency and this is equally applied to non-sinusoidal waveforms. Electromagnetic radiation exhibits wave-like properties and particle-like properties at the same time. X-rays are generated when electrons accelerated to a very high speed rapidly decelerate. The absorption of X-rays by a matter takes place in two distinct ways: scattering and true absorption. These two processes constitute the total absorption characterized by the quantity alp. True absorption arises from electronic transitions within the atom.
