Question

If a is edge length of a face centered cubic unit cell, then the distance of closest approach of two atoms is:

• A. $0.866a$
• B. $1.732a$
• C. $0.707a$
• D. $1.414a$

Answer 1

Answer: (C)

$0.707a$

The distance of closest approach of two particles in a face centred cubic unit cell is the distance between the atom at the corner of the unit cell and the atom at the corresponding centre is =$\frac{a\sqrt{2}}{2}$