Percentage of free space in cubic close packed structure and in body centered packed structure are responsive:

Options

A. 48 % and 26%
B. 30% and 26%
C. 26 % and 32%
D. 32% and 48%

Answer

C

Explanation

for fcc or ccp
`4r = sqrt(2) a`
P.E `=(n xx 4/3 pir^(3))/a^(3)`
`n = 4, a = 2sqrt(2)r`
P.E. `=(n xx 4/3 pir^(3))/a^(3)`
`n = 4, a = 2sqrt(2) r`
P.E `=(4 xx 4/3 pir^(3))/(2sqrt(2) r)^(3)`
P.E = 68%
Free space 32%