$2.$B$3$ MACROSTRUCTURE $(16$ points$)$

A thin cylindrical plate made of iron is approximately $0\mathrm{.}05$ inch thick $(2mm)$ and has a radius of $10$ mm $.$

Assume that all unit cells of the iron plate are arranged so that $"a"$ is perpendicular to the plate surface.

The atomic radius of iron is $0\mathrm{.}124$ nm $.$ Assume the temperature is room temperature $(25C).$

$($a$)$ What is the crystal structure for iron? $(4$ pts$)$ HINT: Look this up online

$($b$)$ Determine the lattice parameter for iron? $(4$ pts$)$

$($c$)$ Determine the total number of unit cells in the plate? $(4$ pts$)$

$($d$)$ State the thickness of the plate in number of unit cells? $(4$ pts$)$