Which of the following series of transitions in the spectrum of hydrogen atom falls in the visible region?

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

The energy of an electron in the second Bohr orbit of a hydrogen atom is:

Calculate the wavelength of the emitted radiation when an electron transitions from $n = 3$ to $n = 2$ in a hydrogen atom. To which region does this radiation belong?

What is the amount of energy associated with the first orbit of a monopositive helium ion? $[R_{H} = 2.18 \times 10^{-18} \ J]$

The frequency of a line in the Pfund series of a hydrogen atom is $2.340 \times 10^{14} \ Hz$. The value of the quantum number $n_2$ for this transition is .....