Please help me answer this :
Knowing that the spacing of adjacent atoms in sodium
chloride crystal is a = 0.282 nm (Fig. 1). X rays with a wavelength of 0.125 nm
are sent through this crystal.
a/ If diffraction from planes parallel to a cube face is considered, at what angles of
the incoming beam relative to the crystal planes will maxima be observed?
b/ Repeat part a/ for diffraction produced by the inclined planes shown in Fig. 1,
which are separated by a/(root of 2)