# FCC and HCP Metallic Crystals MCQ’s

This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “FCC and HCP Metallic Crystals”.

1. Number of particles in one unit cell of HCP lattice is:
a) 1
b) 2
c) 4
d) 6

2. Standard axial ratio for metallic HCP lattice is 2√( 2/3). It is the ratio of
a) Atomic radius to hexagon edge length
b) Hexagon height length to atomic radius
c) Atomic radius to hexagon height
d) None of the mentioned

3. Coordination number of HCP and FCC lattices respectively are:
a) 12, 12
b) 4, 4
c) 12, 8
d) 8, 8

4. The void fraction is the ratio of unfilled volume to total volume of a structure. For ideal metallic FCC crystal, it is:
a) 0.22
b) 0.26
c) 0.32
d) 0.38

5. An octahedral void is present at each edge of the FCC lattice. How much of each of these voids belong to each unit cell?
a) One-eighth
b) One-sixth
c) One-fourth
d) Half

6. Density is the ratio of the mass of crystal to its volume. For a perfect FCC metallic crystal, the mass of a unit cell is 4 times M0. M0 is:
a) specific mass
b) molar mass
c) atomic mass
d) none of the mentioned

7. If N is the number of tetrahedral voids in a close-packed structure, then the number of octahedral voids is:
a) N/4
b) 4N
c) 2N
d) N/2

8. The edge length of an FCC lattice is X times the atomic radius. Value of X is:
a) 2
b) 2√2
c) 4/√3
d) 3/√2

9. A maximum of 74% packing efficiency can be achieved for crystalline solids.
a) True
b) False

10. Which of the following quantities is larger in HCP as compared to FCC if the constituting atoms are similar?
a) Number of particles per unit cell
b) Volume per unit cell
c) Mass per unit cell
d) All of the mentioned 5 Star
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