Q. Total volume of atoms present in a face centred cubic unit cell of a metal is (r=atomic radius )
A) $\frac{20}{3}\pi r^{3}$
B) $\frac{24}{3}\pi r^{3}$
C) $\frac{12}{3}\pi r^{3}$
D) $\frac{16}{3}\pi r^{3}$
Explanation
(d)
Volume of an atom $= \frac{4}{3}\pi r^{3}$
In fcc, number of atoms per unit cell = 4
$\therefore$ Volume of total atoms $= 4 \times \frac{4}{3}\ \pi r^{3}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \frac{16}{3}\pi r^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.