The spectral series observed for the hydrogen atom found in the visible region is

What is the shortest wavelength present in the Paschen series of spectral lines (in $;nm$)?

Ratio of the wavelengths of the first line of the Lyman series and the first line of the Balmer series is

The ratio of the wavelengths of the first Lyman line and the second Balmer line of the hydrogen atom is

The ratio of momentum of the photons of the 1st and 2nd line of Balmer series of Hydrogen atoms is $\alpha/\beta$. The possible values of $\alpha$ and $\beta$ are:-

The shortest wavelength in the Balmer series of a hydrogen atom is equal to the shortest wavelength in the Brackett series of a hydrogen-like atom of atomic number $Z$. The value of $Z$ is: