7. Iron (Fe) has a bcc crystal structure. The atomic number of Fe is 26 and atomic radius is 0.126 nm.

(a) Give the miller indices and calculate the 2 values of the first 3 peaks in the XRD pattern of Fe, assuming the x-ray wavelength used in the measurement is 0.154 nm (Cuk). (b) When Fe and platinum (Pt) is mixed with a certain atomic ratio, they can form a Pt-Fe alloy with an fcc structure. Assuming the lattice constant of the alloy is 0.386 nm. Give the miller indices and calculate the 2 values of the first 3 peaks in the XRD pattern of the Pt-Fe alloy, assuming the x-ray wavelength used in the measurement is 0.154 nm (Cuk).