Question

What is the percentage of void space in bcc type of unit cell?

• A. $68\ %$
• B. $26\ %$
• C. $74\ %$
• D. $32\ %$

Hint:

Packing efficiency: SC = 52%, BCC = 68%, FCC = 74%.

Answer 1

The Correct Option is D

Step 1: Packing efficiency of BCC lattice.
The packing efficiency of a body-centered cubic (bcc) unit cell is approximately $68\ %$. This represents the fraction of space occupied by atoms.

Step 2: Calculation of void space.
Void space is the unoccupied volume in the unit cell and is calculated as:
\[ \text{Void space} = 100% - \text{Packing efficiency} \]
Step 3: Substitution of values.
\[ \text{Void space} = 100 - 68 = 32\ % \]
Step 4: Conclusion.
Hence, the percentage of void space in a bcc unit cell is $32\ %$.