The ratio of energies of photons produced due to the transition of an electron in a hydrogen atom from its $(a)$ second to first energy level and $(b)$ highest energy level to the second level is:

In the Bohr model of the hydrogen atom,what is the energy required to remove an electron from the ground state $(n = 1)$ (in $eV$)?

The first excited state of a hydrogen atom is $10.2 \, eV$ above its ground state. The temperature needed to excite hydrogen atoms to the first excited level is

In an atom,an electron requires $47.2 \, eV$ of energy to transition from the $n = 2$ orbit to the $n = 3$ orbit. The atomic number $Z$ of the atom is:

The energy of an electron in the fourth excited state of the hydrogen atom is

An electron of a hydrogen-like atom,having $Z=4$,jumps from the $4^{\text{th}}$ energy state to the $2^{\text{nd}}$ energy state. The energy released in this process will be $......... \text{eV}$.
(Given $Rch = 13.6 \text{ eV}$)
Where $R =$ Rydberg constant,
$c =$ Speed of light in vacuum,
$h =$ Planck's constant.