The binding energy of an electron in a $H$-atom with $n = 4$ is ....... $eV$. (Magnitude only)

If the binding energy of the electron in a hydrogen atom is $13.6 \ eV$,the energy required to remove the electron from the first excited state of $Li^{++}$ is.....$eV$.

According to the Bohr atom model,in which of the following transitions will the frequency be maximum?

The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths,$\lambda_1/\lambda_2$,of the photons emitted in this process is

Due to transitions among its first three energy levels,a hydrogenic atom emits radiation at three discrete wavelengths $\lambda_1, \lambda_2$ and $\lambda_3$ (where $\lambda_1 < \lambda_2 < \lambda_3$). Then,

$A$ hydrogen atom (ionisation potential $13.6 \ eV$) makes a transition from the third excited state to the first excited state. The energy of the photon emitted in the process is.......$eV$.