Problem 3: (2 Mark) A Debye-Scherrer powder diffraction experiment using incident copper (Cu) radiation gave the following set of reflections expressed as 2 Ka 0:38.40°; 44.50°; 64.85°; 77.90°; 81.85°; 98.40°; 111.20°. (a) 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 based on the hard-sphere approximation calculate the atomic radius. (0.5 Mark) (d) Calculate the density of this element which has an atomic weight of 66.6 g/mol. (0.5 Mark)