Paschen series is obtained when all the transitions of electron terminate on:

Explanation

The Paschen series is obtained when all the transitions of an electron in a hydrogen atom terminate on the n = 3 energy level. In other words, the electrons involved in the transitions in the Paschen series move from higher energy levels to the third energy level (n = 3) and emit photons with specific wavelengths corresponding to these transitions. The lines in the Paschen series are typically in the infrared part of the electromagnetic spectrum. This series is an important component of the hydrogen spectral lines and plays a significant role in understanding the energy levels and atomic structure of hydrogen.