CCP is ABC ABC ...... type packing (A) In topmost layer, each atom is in contact with 6 atoms in same layer and 3 atoms below this layer. Packing fraction=
4×
4
3
πr2
(
4r
√2
)2
=(0.74) (C) Each FCC unit has effective no of atoms = 4 Octahedral void = 4 Tetrahedral void = 8 (D) 4r=a√2