The diagram shows the lowest four energy levels for an electron in a hypothetical atom. The electron is excited to the $-1\, eV$ level and transitions to the lowest energy state by emitting exactly two photons. Which of the following energies could not belong to either of the photons (in $, eV$)?

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 ......... $eV$.

The energy levels of an atom are shown below. When an electron makes a transition from an energy level of $2E$ to an energy level of $E$,the wavelength of the emitted electromagnetic radiation is $\lambda$. What is the wavelength of the emitted photon when the electron makes a transition from an energy level of $4E/3$ to an energy level of $E$?

$A$ monochromatic light is incident on a hydrogen sample in the ground state. Hydrogen atoms absorb a fraction of light and subsequently emit radiation of six different wavelengths. The frequency of incident light is $x \times 10^{15} \ Hz$. The value of $x$ is (Given $h = 4.25 \times 10^{-15} \ eVs$)

$A$ difference of $5.4 \ eV$ separates two energy levels in an atom. What is the frequency of radiation emitted when the atom makes a transition from the upper level to the lower level? (Take $1 \ eV = 1.6 \times 10^{-19} \ J$,$h = 6.625 \times 10^{-34} \ Js$)

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