Step 1: Calculate the number of moles of Ag.
Given mass of Ag is
\[
540 \, \text{g}
\]
Atomic weight of Ag is
\[
108 \, \text{g mol}^{-1}
\]
Therefore, number of moles of Ag is
\[
\frac{540}{108}=5
\]
So, \(540 \, \text{g}\) of Ag contains
\[
5N_A
\]
Ag atoms.
Step 2: Relate atoms and tetrahedral voids in fcc lattice.
In a close-packed structure such as fcc lattice, the number of tetrahedral voids is twice the number of atoms present.
Therefore,
\[
\text{Number of tetrahedral voids}=2 \times \text{number of atoms}
\]
Step 3: Calculate total tetrahedral voids.
Here, number of Ag atoms is
\[
5N_A
\]
Hence, total number of tetrahedral voids is
\[
2 \times 5N_A
\]
\[
=10N_A
\]
But in an fcc unit cell, there are \(4\) atoms and \(8\) tetrahedral voids.
For \(5N_A\) atoms, the number of fcc unit cells is
\[
\frac{5N_A}{4}
\]
Each fcc unit cell contains
\[
8
\]
tetrahedral voids.
Thus, total tetrahedral voids are
\[
\frac{5N_A}{4}\times 8
\]
\[
=10N_A
\]
Step 4: Final conclusion.
Therefore, the total number of tetrahedral voids present in \(540 \, \text{g}\) of Ag metal is
\[
\boxed{10N_A}
\]