The total volume of atoms present in face-centred cubic unit cell of a metal is (r is atomic radius) (a) r (b) r (c) r (d) r

For FCC crystal, Number of atoms = 4 Volume of single atom = 3 4 πr 3 Total volume of atoms= 3 3 4 16 4 3 3 r r x Hence the correct answer is option (d)