Question

The number of atoms in a unit cell of a cubic crystal system is $2$, the arrangement of atoms is:

• A. body centred cubic
• B. face centred cubic
• C. edge centred cubic
• D. simple cubic

Answer 1

The correct option is A body centred cubic

In $BCC$, $8$ atoms are at each of the $8$ corners with each having contribution of $\frac{1}{8}$.

So, the total number of atoms $=\frac{1}{8}\times 8=1$ and $1$ atom is at the center of the cube.

Therefore, a total of $2$ atoms are there in $BCC$.

So, the correct option is ( A )