The spectral series formed when electrons of excited hydrogen atoms return to the third orbit from higher energy orbits is

\begin{array}{lc} \hline Name of spectral series & \begin{array}{l} Excited electrons of \\ hydrogen return to \\ orbit number \end{array} \\ \hline Lyman series & 1 \\ \hline Balmer series & 2 \\ \hline Paschen series & 3 \\ \hline Brackett series & 4 \\ \hline Pfund series & 5 \\ \hline \end{array} Hence, the spectral series formed will be of Paschen series.