If an electron falls from $n = 3$ to $n = 2$,then the emitted energy is $..........$ $eV$.

The energy difference of two stable orbits of Hydrogen is $214.68 \ kJ \ mol^{-1}$. If the transition of an electron takes place,find the emitted frequency. (Note: $v = \Delta E/h$ and $h = 6.626 \times 10^{-34} \ J \ s$)

What is the experimental evidence in support of the idea that electronic energies in an atom are quantized?

The electronic energy levels of the hydrogen atom in the Bohr's theory are called

The light of wavelength $242 \, nm$ is required to remove an electron from a $Na$ atom. What is the ionization energy of the sodium atom in $kJ \, mol^{-1}$?

Give names of atomic models and write about Thomson model.