Question

In the fcc structure, the number of tetrahedral holes per sphere is

• A. \(1\)
• B. \(4\)
• C. \(2\)
• D. \(8\)

Hint:

An fcc cell has 4 spheres and 8 tetrahedral holes.

Answer 1

The Correct Option is C

Step 1: Locate the holes:
Each of the 8 small cubes in an fcc cell has one tetrahedral hole at its body centre.

Step 2: Count atoms:
The cell has $8\times\frac18 + 6\times\frac12 = 4$ atoms.

Step 3: Ratio:
$8/4 = 2$ per sphere, option (C).

Final Answer:
Two tetrahedral holes per sphere. \[ \boxed{\text{(C) }2} \]