Question

Total volume of atoms present in a face centred cubic unit cell of a metal is ........ (r is atomic radius)

(A) \(\cfrac{8}{3}\pi r^3\) 

(B) \(8\pi r^3\)

(C) \(\cfrac{16}{3}\pi r^3\)

(D)\(\cfrac{4}{3}\pi r^3\)

Answer 1

Correct answer is: (C)\(\cfrac{16}{3}\pi r^3\)

Volume occupied by one atom of radius ‘r’=\(\cfrac{4}{3}\pi r^3.\)

\(\therefore\)In fcc unit cell, there are 4 atoms present.

present in fcc unit cell = \(4\times\cfrac{4}{3}\pi r^3=\cfrac{16}{3}\pi r^3\)