Determine the crystal structure. (0.5 Mark) (b) Calculate the lattice constant, a. (0.5 Mark) (c) Assume that the crystal is a pure metal and on the basis of the hard-sphere approximation calculate the atomic radius. (0.5 Mark) (d) At what angle would we find the first reflection if, instead of K radiation, we used silver L radiation to illuminate the specimen? (0.5 Mark)