If $Z$ is the number of atoms in the unit cell that represents the closest packing sequence $ABCABC .....,$ the number of tetrahedral voids in the unit cell is

How will you distinguish between the following pairs of terms:
$(iii)$ Tetrahedral void and octahedral void?

Calculate the packing efficiency in a simple cubic unit cell.

In crystalline silicon,$Si$ atoms occupy all the $ccp$ sites and every alternate tetrahedral void. The value of packing efficiency is closest to $....\%$

$A$ compound is formed by elements $A$, $B$ and $O$. Atoms of oxygen form $ccp$ lattice. Atoms of $A$ (cation) occupy $\frac{1}{8}^{\text{th}}$ of tetrahedral voids and atoms of $B$ (cation) occupy half of octahedral voids. What is the molecular formula of the compound?

In a cubic close packed structure,the fractional contributions of an atom at the corner and at the face in the unit cell are,respectively: