The frequency of the limiting line of the Lyman series in the hydrogen spectrum is ....

For ionising an excited hydrogen atom,the required energy in $eV$ will be -

The frequency of a certain line of the Lyman series of the atomic spectrum of the $H$ atom satisfies the following conditions:
$(i)$ It is the sum of the frequency of another Lyman line and a Balmer line.
$(ii)$ It is the sum of the frequency of a certain line,a Lyman line,and a Paschen line.
$(iii)$ It is the sum of the frequency of a Lyman and a Paschen line but no Brackett line.
To what transition does this frequency correspond?

In the atomic spectrum of hydrogen,the series of lines observed in the visible region is:

Ionisation energy of $He^{+}$ is $19.6 \times 10^{-18} \, J \, atom^{-1}$. The energy of the first stationary state $(n = 1)$ of $Li^{2+}$ is

The frequency and energy of a photon with a wavelength of $4000 \ \mathring{A}$ are respectively.......