Material Science- x-ray diffraction and metal densities

[maiad]

Homework Statement

Consider a metal with an BCC crystal structure and atomic weight 92.91. When monochromatic x-radiation having a wavelength of 0.14 nm is used, the angle of diffraction (2*theta) for the (211) set of planes in this metal occurs at 41.148 ° (first-order reflection).


Compute the density of this metal in g/cm^3


The sin function requires input in radians.


Use decimal notation, digits after decimal: 2

Homework Equations

a=4R/sqrt(3)

p=n*A/V*N

n*lamba=2d(hkl)sin(theta)

d(hkl)=a/sqrt(h^2 +k^2 + l^2)

The Attempt at a Solution

i basically broke down the equation into P=(2Asin(theta)) / ((a^2)(sqrt(h^2+k^2+l^2))

but for the vaule of a... i don't have the radius to find the vaule of a soo any hints would be nice :)

 

[Borek]

n*lamba=2d(hkl)sin(theta)

What is known, what is unknown?