Q3. (40 points) Diffraction pattern for polycrystalline a-iron (BCC) is provided below. The X-Ray used to do the measurement is Copper K-a with wavelength of 0.15406nm. Please calculate (1) d110, and d200, and (2) based on the information from (1) to calculated the PD on (110), and (200) planes. Hint: unit cell edge a can be obtained from d measured