Given that,

Energy in the first excited state \(=23.8\,eV\)

Now, we know that,

Total energy of any level in hydrogen atom is \(E =-\frac{13.6}{ n ^2}\,eV\)

For ground state

\(E _{ g }=-13.6\,eV\)

Now, for exited state

\(E _{ e }=-\frac{13.6}{4}\,eV\)

\(E _{ e }=-3.4\,eV\)

Now, the potential of ground state

\(P . E=2 \times(-13.6)\)

\(P . E=-27.2\,eV\)

Now, if we assume, it is zero now means we increase hydrogen energy level by

\(27.2\,eV\) energy

So, now in first excited state it has total energy of \(=-3.4+27.2\)

\(=23.8\,eV\)