Bragg's Law of Diffraction, Define Bragg's Law, Bragg's Law Derivation

Bragg's Law of Diffraction, Define Bragg's Law, Bragg's Law Derivation

BRAGG’S EQUATION FOR X-Ray DIFFRACTION

When monochromatic X-Rays are incident as a crystal they get scattered by the crystal atom Brag propounded a law the constructive diffraction which is called the Bragg’s Law.

According to Bragg’s Law if d is the separation between the two nearest plane and Q is the glancing angle of the incident X-Ray with the crystal plane then for the constructive diffraction.

Consider a crystal in which atoms are arranged in a periodic manner with interatomic spacing ‘d’. A narrow beam of monochromatic X-Ray of wavelength λ is allowed to fall on a crystal at a glancing angle θ. The crystal acts as a diffracting grating with atoms as the opaque part and the spacing between them as the transparent part.

Let AB and DE be the incident rays and BC and EF be the corresponding reflected rays the path difference between the rays ABC and DEF is (GE+EH) therefore the path difference is given by

Constructive interference takes place only when the path difference is equal to nλ that is when the following condition satisfied