Question 8: Why it is not possible to obtain diffraction of X-rays by Young’s double slit experiment?
Diffraction of waves can be observed only when the width of the slits is comparable (less than or equal to) to the incident wave. Now X-rays are electromagnetic radiations with wavelengths in the range of 0.1 to 10 Ansgstroms. This is so small that in practice such a small width cannot be produced by Young’s double slit experiment. While on the other hand,wavelength of light is (4000 to 7000 Angstrom) greater than the wavelength of X-rays. Therefore,Young’s double slit experiment arrangements can be used for light but not for X-rays.
For the diffraction of X-rays, crystals like NaCl are used which has a comparable atomic spaces as that of wavelength of X-rays.