Question

Copper has face-centered cubic (fcc) lattice with interatomic spacing equal to 2.54. The value of lattice constant for this lattice is:

• A. 3.59 A
• B. 2.54 A
• C. 1.27 A
• D. 5.08 A

Answer 1

The correct option is A 3.59 A

Given interatomic spacing = 2r = 2.54 $A^o$

In FCC lattice, $4r=\sqrt{2}a$ ,where a is lattice constant.

$2r=\frac{\sqrt{2}a}{2}=\frac{a}{\sqrt{2}}$

$a=2r\times \sqrt{2}=\left(2.54A^o\right)\left(1.414\right)=3.59A^o$

So correct option is A..