QS Study

The significance of Bragg’s equation

(1) If we use X-rays of known wavelength (λ), then the interatomic distance (d) in an unknown crystal can be calculated. On the other hand, if we use a crystal whose interatomic distance ‘d’ is known, then the wavelength of X-rays can be calculated.

(2) The Bragg’s equation gives the essential condition for diffraction to occur.

(3) When the experiment is done, there will be a maximum reflection at a particular angle θ. That angle is noted. It corresponds to first order reflection (n=1). If the angle ‘θ’ is increased, maximum reflection occurs at some other higher angle. It corresponds to second-order reflection (n=2). Similarly, third, fourth and higher order of reflection occurs at certain specific angles.

The values of angles obtained are in accordance with the Bragg’s equation. Hence Bragg’s equation is experimentally verified.