Question

Percentage of free space in cubic close-packed structure and in body centred packed structure are, respectively:

• A. $30\%$ and $26\%$
• B. $26\%$ and $32\%$
• C. $32\%$ and $48\%$
• D. $48\%$ and $26\%$

Answer 1

The correct option is B $26\%$ and $32\%$

Packing fraction of cubic close packing and body centred packing are 0.74 and 0.68 respectively.
Therefore the free space are respectively 26% and 32%.