When white radiation is passed through hydrogen gas at room temperature,in the absorption spectrum dark lines are observed only in Lyman series why?

The Lyman series of lines is due to transitions from higher-energy orbits to the lowest-energy orbit (n = 1); these transitions release a great deal of energy, corresponding to radiation in the ultraviolet portion of the electromagnetic spectrum. The Paschen, Brackett, and Pfund series of lines are due to transitions from higher-energy orbits to orbits with n = 3, 4, and 5, respectively; these transitions release substantially less energy, corresponding to infrared radiation. Thus, when white radiation is passed through hydrogen gas at room temperature,in the absorption spectrum dark lines are observed only in Lyman series.