The vacant space in bcc lattice unit cell is :

Options

A. `23%`
B. `32%`
C. `26%`
D. `48%`

Answer

2

Explanation

In whatever way the constituent particles (atoms molecules or ions)are packed there is always some free space in the form of voids . The percentage of total available space filled by the particles is called packing efficiency.
volume occupied by two spheres
`=("in the unit cell")/("Total volume of the unit cell")xx100%`
`=(2xx(4//3)pir^(3))/((4//3r^(3)))xx100%`
`=((8//3)pit^(3))/(64(3sqrt(3))r^(3))xx100%`
`68%`
therefore `%` vacant space in bcc lattice unit cell =`100%-68%`
`=32%`