What is the ratio of number of atoms per unit cell to the number of T-voids in cubic close packing?
Answer & explanation
Correct answer: option 2
The correct answer is option 2. 1 : 2.
In Cubic closed packing, unit cell is of fcc type
(i) No. of atoms per unit cell = \(\frac{1}{8}\) x 8 + \(\frac{1}{2}\) x 6 = 1 + 3 = 4
(ii) No. of T-voids in a unit cell = 8
Ratio of (i) and (ii) is 4 : 8 or 1 : 2