Atoms which can be assumed to be hard pusher of radius $R,$ are arranged in bcc lattice with lattice content $a,$ such that each atom touches its nearest neighbours. Take the centre of one atom as the origin. Another atom of radius $r($assumed to be hard sphere$)$ is to be accommodated at a position $(0,\frac{a}{2},0)$ without distorting the lattice. The maximum value of $\frac{r}{R}$ is

Correct to $3$ decimal places.

YOURANSWER

$0\mathrm{.}155$

$0\mathrm{.}413$ to $0\mathrm{.}414$