JIPMER2010ChemistrySolid State
If a be the edge length of the unit cell and r be the radius of an atom then for fcc arrangement, the correct relation is
Options
- A4 a= 3 r
- B4 r= 3 a
- C4 r= 2 a
- D4 r= a 2
Correct answer
C. 4 r= 2 a
Step-by-step solution
Given, the edge length of the unit cell =a and, radius of the sphere =r Consider A B C , aligned A C^2 & =A B^2+A C^2 & =a^2+a^2 & =2 a^2 A C & = 2 a aligned But, from the figure, A C=4 r 4 r= 2 a