The total energy of an electron revolving in the second orbit of a hydrogen atom is

$A$ hydrogen atom is bombarded with electrons accelerated through a potential difference of $V$, which causes excitation of hydrogen atoms. If the experiment is performed at $T = 0 \,K$, the minimum potential difference needed to observe any Balmer series lines in the emission spectra will be $\frac{\alpha}{10} \,V$, where $\alpha = $ . . . . . . .

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.....$eV$.

Some of the wavelengths observed in the emission spectrum of neutral hydrogen gas are $912, 1026, 1216, 3646, 6563 \, \mathring{A}$. If broadband light is passing through neutral hydrogen gas at room temperature,then the wavelength that will not be absorbed strongly is .................. $\mathring{A}$.

Total energy of an electron in an excited state of a hydrogen atom is $-3.4 \text{ eV}$. Find the kinetic and potential energy of the electron in this state.