Step 1: Write the total energy formula for hydrogen atom.
The total energy of an electron in the \(n^{th}\) orbit is
\[
E_n=\frac{-13.6}{n^2}\;eV
\]
For \(n=4\),
\[
E_4=\frac{-13.6}{4^2}
\]
\[
E_4=\frac{-13.6}{16}
\]
\[
E_4=-0.85\;eV
\]
Step 2: Relate potential energy and total energy.
For a hydrogen atom,
\[
U=2E
\]
where \(U\) is potential energy.
Therefore,
\[
U=2(-0.85)
\]
\[
U=-1.7\;eV
\]
Step 3: Final conclusion.
Hence, the potential energy of the electron in the excited state is
\[
\boxed{-1.7\;eV}
\]