Question

Your x-ray lab has a monochromator consisting of a single crystal of nickel cut so that the plane lies in the cube face. At what angle (in degrees) should the cube face be tilted with respect to the incident beam in order to select radiation with a wavelength ? The lattice constant of nickel is .

Answer 1

(111) plane
wavelengt ambda= 3.091 A
lattice constant is alpha = 3.53 A

Answer 2

n*wavelength = 2d*sin theta.
I presume you want n = 1.