Question

calculations of fcc and bcc​

Answer 1

Answer:

In a FCC lattice there rer 8 atoms at eight corners and 6 at face centers,

Now each corner contributes to eight cells so per unit cell contribution is

8

1

×8=1 atom.

Now similarly each face center contributes to two unit cells so contribution per unit cell by six face centers is equal to

2

1

×6=3 atoms. Hence total no. of atoms per unit cell of FCC lattice is (1+3)=4 atoms.

Answer 2

Answer:

Explanation:

In a FCC lattice there rer 8 atoms at eight corners and 6 at face centers,

Now each corner contributes to eight cells so per unit cell contribution is

8

1

​

×8=1 atom.

Now similarly each face center contributes to two unit cells so contribution per unit cell by six face centers is equal to

2

1

​

×6=3 atoms. Hence total no. of atoms per unit cell of FCC lattice is (1+3)=4 atoms.

For BCC-

A bcc has one atom in center and

8

1

​

th part of 8 corner atoms i.e 1 atom.

In total there are 1+1=2 atoms.