The shortest wavelength in the Paschen series of the Hydrogen spectrum is (Rydberg constant of hydrogen $R_H = 1.097 \times 10^7 \ m^{-1}$). (in $nm$)

The ratio of the shortest wavelength of the Balmer series to the shortest wavelength of the Lyman series for a hydrogen atom is:

The wavelength of light for the least energetic photons emitted in the Lyman series of the hydrogen spectrum is nearly. [Take $hc = 1240 \text{ eV-nm}$, change in energy of the levels $= 10.2 \text{ eV}$] (in $\text{ nm}$)

Which series of the hydrogen spectrum was observed first?

The electron in a hydrogen atom is initially in the third excited state. When it finally moves to the ground state,the maximum number of spectral lines emitted is:

What is the wavelength of the least energetic photon emitted in the Lyman series of the hydrogen atom spectrum? (in $nm$)