The radius of the largest shpere which fits properly at the centre of the edge of a body centred cubic unit cell is : (Edge length is represented by 'a')

Options

A. 0.047 a
B. 0.027 a
C. 0.134 a
D. 0.067 a

Explanation

For bcc lattice ` sqrt(3) a = 4 r `
Let the radius of sphere which fits at the edge centre in R.
r + 2R + r = a
`R = (a - 2r)/(2) = ((4r)/(sqrt(3)) - 2r)/( (4)/(2)) , (2a - sqrt(3)a)/(2 xx 2) = 0.067 ` g