The packing efficiency of a simple cubic crystal with an interstitial atom exactly fitting at the body centre is : 

Options

A. `0.48`
B. `0.52`
C. `0.73`
D. `0.91`

Answer

C

Explanation

Here the interstilal atom is exactly fitting at the body centre
`therefore r_(+)/r^(-) = 0.732, therefore P.E = 4/3 pi ((r^(+))^(3) + 4/3 pi(r^(-))^(3))/a^(3) , 2r^(+) + 2r^(-) = sqrt(3)a` By solving we will get 0.73