If the body-centered unit cell is assumed to be a cube of edge length 'a' with spherical particles of radius 'r' then how is the diameter, d of particle and surface area, S of the cell related?

MCQs on solid state characteristics, amorphous solids, crystalline solids and its classification, crystal lattices, unit cells, close packed structures, packing efficiency, unit cells calculations, solids imperfections, solid state electrical and magnetic properties.