Question

Total volume of atoms present in a face-centred cubic unit cell of a metal (r is atomic radius) is ______.

Options

• `20/3  pi r^3`

• `24/3  pi r^3`

• `12/3  pi r^3`

• `16/3  pi r^3`

Answer 1

Total volume of atoms present in a face-centred cubic unit cell of a metal (r is atomic radius) is `bbunderline(16/3  pi r^3)`.

Explanation:

In an fcc unit cell, there are 4 atoms per unit cell.

Each atom is assumed to be spherical with radius r.

The volume of one atom = `4/3  pi r^3`

∴ Total volume = `4 xx 4/3  pi r^3`

= `16/3  pi r^3`