Assertion: X− rays cannot be diffracted by means of grating.
Reason: X− rays do not obey Bragg’s law.
A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If the assertion is true but the reason is false.
D. If the assertion and reason both are false

Hint: The angles for coherent and incoherent scattering from a crystal lattice are provided by Bragg's equation. In this question, we will try to relate the wavelength of X-rays with the dispersive tendency of grate. Gratings have no absorption effects and provide a linear dispersion of wavelengths.

Complete step by step solution:
One of the imaging techniques utilized in medical science is X-ray diffraction photography. This approach uses X-rays to diffractionally identify the structure and molecular arrangement of the object on which it falls. It provides the scattering angles from a crystal lattice for both coherent and incoherent scattering. Additionally, the waves with the same frequency are re-radiated by the movement of charges. Rayleigh's scattering is another name for this phenomenon.

Identification of materials based on their diffraction pattern is the main application of X-ray diffraction analysis. The x-ray diffraction method in phase identification also reveals how interior flaws and stresses cause the ideal structure to deviate from the actual one. Crystal atoms primarily interact with their electrons to scatter incident X-rays. Elastic scattering is the term used to describe this phenomenon; the electron is the scatterer.

Orbicular waves are always displayed by a regular array of scatterers. These waves interfere destructively in the vast majority of directions, however Bragg's law states that they combine constructively in less obvious directions. The X-ray wavelength (A) is extremely small. They therefore cannot be diffracted by means of a regular grate. Bragg's law is observed by X-rays.

Hence option C is correct.

Note: One of the first techniques for researching the structure of solids is called X-ray diffraction. Electromagnetic waves with the same frequency but different phases interact during the diffraction process to create both constructive interference (bright spots on the film exposed to light) and destructive interference (dark spots).