Solid State Question 6
Question 6 - 01 February - Shift 2
A metal $M$ crystallizes into two lattices :- face centred cubic (fcc) and body centred cubic (bcc) with unit cell edge length of 2.0 and $2.5 \AA$ respectively. The ratio of densities of lattices fcc to bcc for the metal $M$ is
(Nearest integer)
Show Answer
Answer: (4)
Solution:
$ d=\frac{Z \times M}{N_A a^{3}} $
$\frac{d _{FCC}}{d _{BCC}}=\frac{\frac{4 \times M_w}{N_A \times(2)^{3}}}{\frac{2 \times M_w}{N_A \times(2.5)^{3}}}=3.90$
