The minimum and maximum values of wavelength in the Lyman series of a H atom are, respectively



 

For lyman series,
Maximum wavelength implies minimum transition energy which is for n₂ =2→n₁ =1,E=10.4eV.
Minimum wavelength implies maximum transition energy which is for n₂ =∞→n₁ =1,E=13.6eV.
Therefore,
λ_max =hc/E _min =121nm, 
λ _min =hc/E _max =91nm.