What is the lowest energy of the spectral line emitted by the hydrogen atom in the Lyman series?
(h = Planck constant, c = Velocity of light,R = Rydberg constant)

Lowest energy is emitted when ${\mathrm{n}}_2={\mathrm{n}}_1+1$ 

Thus in Lyman series 2 → 1 will have least energy

                      $\mathrm{E}=\frac{3{\mathrm{hcR}}_{\mathrm{H}}}{4}$