The four lowest energy levels of an $H$-atom are shown in the figure. The number of possible emission lines would be

The energy required to excite an electron from the ground state of a hydrogen atom to the first excited state is:

The energy of a hydrogen atom in its ground state is $-13.6 \, eV$. The energy of the level corresponding to the quantum number $n = 5$ is ...... $eV$.

The energy levels of an atom are shown in the figure. Which one of these transitions will result in the emission of a photon of wavelength $124.1 \, nm$? Given $(h = 6.62 \times 10^{-34} \, Js)$.

In a hydrogen atom,the electron makes a transition from the $(n+1)^{\text{th}}$ level to the $n^{\text{th}}$ level. If $n >> 1$,the frequency of the radiation emitted is proportional to:

Some energy levels of a molecule are shown in the figure. The ratio of the wavelengths $r = \frac{\lambda_1}{\lambda_2}$ is given by