11. What is "Atomic Packing Factor (APF)" for Face Centered Cubic (FCC) unit cell? 0.52 0.68 0.72 0.74 12. What is the definition of Polycrystalline? * Solids that consist of many small crystals (the grains). Solid that has no organization (not a crystalline structure). Solid that consist of a noninterrupted repetition of the unit cell in three dimensions. Solid that consist of interrupted repetition of the unit cell in three dimensions. 13. Calculate theoretical density for Copper (Cu) given that it has a face centered cubic structure, and the atomic weight is 52 g/mole. We are also given the atomic radius of 0.125 nm? 14.352 g/cm3 7.814 g/cm3 10.823 g/cm3 7.182 g/cm3