Q31 / 155 · WBJEE 2017 · Chemistry
In a close-packed body-centred cubic lattice of potassium, the correct relation between the atomic radius $(r)$ of potassium and the edge-length of the cube is
- A$r=\frac{a}{\sqrt{2}}$
- B$r=\frac{a}{\sqrt{3}}$
- C$r=\frac{\sqrt{3}}{2} a$
- Correct answerD$r=\frac{\sqrt{3}}{4} a$
Solution
$\because$ For be packing, $\sqrt{3} a=4 r \therefore r=\frac{\sqrt{3}}{4} \cdot a$
where $a=$ edge length $r=$ radius of lattice sphere
Hence, the correct answer is option: 'D'.