The edge length of cubic unit cell of metallic calcium is $556\;pm$ If the density of calcium is $1.54 \;g\;cm^{-3}$ and its molar mass is $40.08];g\;mol^{-1}$ calculate the radius of calcium atom.

Question

$\begin{array}{1 1} 135.5\;pm \\ 415\;pm \\ 678\;pm \\ 196.6\;pm \end{array}$