1.34 Calculate the efficiency of packing in case of a metal crystal for (i) Simple cubic (ii) Body-centred cubic (iii) Face-centred cubic (with the assumptions that atoms are touching each other). 

<p><strong>1.34 (i)</strong> The efficiency of packing in case of simple cubic unit cell is given below:&nbsp;<br>A simple cubic unit cell contains one atom per unit cell.<br>Also, a=2r, where a is the edge length and r is the radius of atom. Total volume of unit cell = a³<br>Packing efficiency = Volume of one sphere / Total volume of unit cell × 100</p><p>Packing Effieciency = 4/3πr³ / 8r³ X 100 = 52.4%</p><p><strong>(ii) </strong>The efficiency of packing in case of body-centred cubic unit cell is given below:<br>A body-centred cubic unit cell containstwo atoms per unit cell.<br>Also, √3a = 4r,where a isthe edge length and r isthe radius of atom.<br>Total volume of unit cell = a³<br>Packing efficiency = Volume of one sphere / Total volume of unit cell × 100</p><p>Packing efficiency = 16/3πr³ / 16√2r³ x 100 = 74%</p>

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