Question

In a unit cell, atoms `(A)` are present at all corner lattices, `(B)` are present at alternate faces and all edge centres. Atoms `(C)` are present at face centres left from `(B)` and one at each body diagonal at disntance of `1//4th` of body diagonal from corner.
Total fraction of voids occupied are
A. `0.58`
B. `0.25`
C. `0.48`
D. `0.86`

Answer 1

Correct Answer - A
There are `8` effective TVs out of which 4 are occpied (one at each body diagonal) and 4 effective Ovs such that one is ot filled (body centre). So out of `12(8 TVs + 4 "Ovs")`, only `7` are occpied `= 7/(12) = 0.58`