Physics - Modern Physics Question with Solution | TestHub

Paragraph:In a mixture of $\mathrm{H}-{\mathrm{H}}^{+}$gas $({\mathrm{He}}^{+}$is singly ionised $\mathrm{He}$ atom), $\mathrm{H}$ atoms and ${\mathrm{He}}^{+}$ions are excited to their respective first excited states. Subsequently, $\mathrm{H}$ atoms transfer their total excitation energy to ${\mathrm{He}}^{+}$ions (by collisions). Assume that the Bohr model of atom is exactly valid.Question:The quantum number $n$ of the state finally populated in ${\mathrm{He}}^{+}$ions is