Question

Which of the following represents the closed packed arrangement of uniform solid spheres?

• A. Simple cubic unit cell
• B. Body-centered cubic unit cell
• C. Face-centered cubic unit cell
• D. HCP unit cell

Answer 1

Answer: (C), (D)

The correct options are
C Face-centered cubic unit cell
D HCP unit cell

Packing efficiency of the simple cubic unit cell is $52\%$ and of bcc is $68\%$.

Packing efficiency of face centred cubic unit cell and hcp is $74\%$.

Since the packing efficiency of face centred cubic unit cell and hcp is maximum and so, they represent the closely packed arrangement of uniform solid spheres.