Question

The contribution of particle at the edge centre to a particular unit cell is,

• A. $\frac{1}{2}$
• B. $\frac{1}{4}$
• C. 1
• D. $\frac{1}{8}$

Answer 1

The correct option is B $\frac{1}{4}$

An edge centered is common to four unit cells. The contribution from each edge atom is hence, 1/4. Think about the edge a cieling near you. Assume that this is a multistorey apartment. The room you are in, the room beside you, and two rooms on the floor above you would share that same edge - that is where the number 4 comes from. So if an atom is placed with equal parts in all the 4 rooms, the contribution from each room would be 1/4.