Question

How many atoms are present in a unit cell of a body-centered cubic (BCC) lattice?

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

Atoms per unit cell: Simple cubic = 1 Body-centered cubic (BCC) = 2 Face-centered cubic (FCC) = 4

Answer 1

The Correct Option is B

Concept: In a body-centered cubic (BCC) unit cell:
• 8 atoms are present at the corners of the cube
• 1 atom is present at the center of the cube Each corner atom contributes \( \frac{1}{8} \) to the unit cell.

Step 1: Contribution from corner atoms. \[ 8 \times \frac{1}{8} = 1 \]

Step 2: Contribution from body-centered atom. The atom at the center belongs completely to the unit cell. \[ =1 \]

Step 3: Total atoms in the unit cell. \[ 1 + 1 = 2 \] \[ \boxed{2} \]