37. The volume atomic density (atom/m
3
) of fcc nickel whose atomic mass is
58.71 kg/k mol and density 8.94 Â 10
3 kg/m
3 is:
(a) 9.17 Â 10
28
(b) 8.17 Â 10
28
(c) 7.17 Â 10
28
(d) 6.17 Â 10
28
38. The volume atomic density (atom/m
3 ) of fcc copper whose lattice parameter is
3.61 Å and atomic mass 63.54 kg/k mol is:
(a) 6.50 Â 10
28
(b) 7.50 Â 10
28
(c) 8.50 Â 10
28
(d) 9.50 Â 10
28
39. The efficiency with which a 2-D arrangement of identical spheres (atoms) on a
square lattice can pack is:
(a) 48.5%
(b) 58.5%
(c) 68.5%
(d) 78.5%
40. The efficiency with which a 2-D arrangement of identical spheres (atoms) on a
hexagonal lattice can pack is:
(a) 90.7%
(b) 80.7%
(c) 70.7%
(d) 60.7%
41. The efficiency with which a 3-D arrangement of identical spheres (atoms) on a
simple cubic lattice can pack is:
(a) 42%
(b) 52%
(c) 62%
(d) 72%
42. The efficiency with which a 3-D arrangement of identical spheres (atoms) on a
body-centered cubic lattice can pack is:
(a) 48%
(b) 58%
(c) 68%
(d) 78%
134
3 Unit Cell Calculations