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NEET levelSingle correct optionDifficulty 1 of 3ss005

The packing efficiency of a simple cubic unit cell is nearest to

A74%
B52.4%
C68%
D32%

Answer: B

In simple cubic

a = 2 r

and

Z = 1

, so packing fraction

= \frac{\frac{4}{3} π r ^{3}}{( 2 r ) ^{3}} = \frac{π}{6} \approx 0.524

, i.e. 52.4%.

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