Sequence of series in hydrogen spectrum are Lyman series (n=1), Balmer series (n=2), Paschen series (n=3), Bracket series (n=4) and Pfund series (n=5). For Lyman series, n1=1 For shortest wavelength in Lyman series i.e., the energy difference in two states showing transition should be maximum i.e., n2=∞ Using formula,
1
λ
=RH[
1
n12
−
1
n22
] hereRH=Rydberg‌constant
1
λ
=RH[
1
12
−
1
∞2
] ⇒
1
λ
=RH λ=
1
RH
=
1
109678
=9.117×10−6‌cm=91.2‌nm Hence, Lyman series is a spectral series of transitions and resulting ultraviolet emission lines of H-atom.