Q. An alloy of copper, silver and gold is found to have copper constituting the $ccp\$lattice. If silver atoms occupy the edge centres and gold is present at body centre, the alloy has a formula
A) $Cu\ Ag\ Au$
B) $Cu_{4}\ Ag_{2}\ Au$
C) $Cu_{4}\ Ag_{3}\ Au$
D) $Cu_{4}\ Ag_{4}\ Au$
Explanation
(c)
Number of Cu atoms at corners $= 8 \times \frac{1}{8} = 1$
Number of Ag atoms at edge centres $= 12 \times \frac{1}{4} = 3$
Number of Au atoms at body centre $= 1 \times 1 = 1$
$\therefore Formula\ is\ {Cu}_{4}{Ag}_{3}Au$.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.