What is the total number of atoms in BCC crystal lattice having $1.8 \times 10^{20}$ unit cells?
What is the total number of atoms in BCC crystal lattice having $1.8 \times 10^{20}$ unit cells?
$9.0 \times 10^{20}$
$1.8 \times 10^{20}$
$3.6 \times 10^{20}$
$7.2 \times 10^{20}$
Solution
In one BCC crystal unit cell number of atoms $(Z)=2$
Total number of atoms $=\mathrm{Z} \times$ Number of unit cells
$\begin{aligned}
& =2 \times 1.8 \times 10^{20} \\
& =3.6 \times 10^{20}
\end{aligned}$